What's in store for the Sweet 16

Forty-nine games are in the books, leaving us with 16 teams battling it out for a trip to San Antonio. Take a look at how they got here and what they need to do to keep going.

East Regional

No. 1 North Carolina (Beat No. 16 Mount St. Mary's 113-74; No. 9 Arkansas 108-77)
How they got here: The Heels steamrolled Mount St. Mary's and Arkansas, easily hanging 100-plus on each overmatched squad. It was a vintage weekend for the No. 2-ranked offense in the land. High tempo + high efficiency = damage to opposing defenses.

Biggest strength: Devastating offense. The Tar Heels are more or less the anti-Wisconsin. Defensively, they can be hit or miss at times, but it doesn't get any better than this offensively. The Heels shot 60.6 percent against Mount St. Mary's and then a ridiculous 67.7 percent against Arkansas. According to bbstate.com's database, the Heels' 1.59 points per possession against the Hogs is the third-best performance in Division I this season. They also committed just 16 turnovers in 144 possessions combined in the two games, despite extended garbage time. If they are going to continue scoring like this, it really won't matter if they occasionally don't stop you. The starting quartet of Tyler Hansbrough, Deon Thompson, Ty Lawson and Wayne Ellington have combined for 145 points in just 186 total minutes. Sick.

Biggest problem: Defensive focus. There's a reason the Heels don't even rank in the nation's top 100 in 2-point field-goal percentage defense. Even Mount St. Mary's found a slew of open looks in the first 20 minutes Friday night. UNC has shown at times this season that it can get stops when it needs to (like the second Duke game), but the consistency is not always there. It will be very interesting to see how the Heels defend the impeccable precision of Washington State in the Sweet 16. No team can completely throttle the Heels down, but if any club can control tempo to a point where it's reasonable, it's the Cougars. The only way Wazzu can take out the Heels is to limit possessions and get a bunch of easy baskets, and the Cougars could find a number of those if the Heels aren't ready to work.

No. 2 Tennessee (Beat No. 15 American 72-57; No. 7 Butler 76-71)
How they got here: The Vols had a surprisingly rough time with No. 15 American before putting the Eagles away in the final four minutes. They then had a not-so-surprisingly tough time with No. 7 Butler, fending off the Bulldogs in overtime to advance.

Biggest strength:
Perseverance and mental toughness. They don't always play the highest quality basketball, but there doesn't appear to be a team that's mentally stronger than the Vols. More often than not, they find a way to will themselves to the finish line, even when things aren't going as planned. They have made the Sweet 16 despite having Chris Lofton shoot a combined 4-for-18 in the two games, missing 27 of 38 3s as a team, getting destroyed on the glass by a Patriot League team and committing 20 turnovers against Butler. Lesser teams would have been picked off by now. This isn't a new trend for Tennessee, though. The Vols have won games this season despite subpar offensive nights and they have won games when they got lit up defensively. Whatever it takes to win, this team usually finds it before it's too late.

Biggest problem:
Cats don't get 10 lives. Tennessee has been inconsistent in many areas in its two NCAA tournament games. The bigger problem might be that the Vols have been mediocre offensively in five of their last nine games and Sweet 16 opponent Louisville is playing too well to make that six of 10 and expect to survive. How will new starting point guard J.P. Prince hold up under the Cards' pressure? He had five assists and six turnovers against Butler, which isn't exactly the mark of a high-pressure, high-athleticism club.

No. 3 Louisville (Beat No. 14 Boise State 79-61; No. 6 Oklahoma 78-48)
How they got here: The Cardinals rolled past Boise State and blasted Oklahoma to cruise into the Sweet 16. They're one of the few teams that hasn't been challenged yet.

Biggest strength: Stingy D. The offense will be getting credit for the audacious shooting numbers in the tournament thus far, but the Cards' calling card this season has been their very tough defense. Louisville's first two opponents combined to shoot 9-of-35 from 3-point range, and Oklahoma shot 31.9 percent overall. That's not much different than what we've seen from a Louisville team that ranked 13th in both 2-point and 3-point shooting defense in the regular season. This is not a great shooting team, even with all the weapons healthy, although Tennessee and then potentially North Carolina aren't the staunchest of defensive outfits. The Cards' hopes will continue to rest on their defense

Biggest problem: Free-throw shooting. There's lots of talk about how bad Memphis and Tennessee can be from the free-throw line. Well, how about Louisville, which ended the season ranked 305th in Div. I from the stripe and has five of its top six scorers shooting under 66 percent from the line? Even in pitching a virtual perfect game against the Sooners in Round 2, the Cards shot an atrocious 5-of-15 from the line. Mix in the 9-for-18 performance in the Boise State game, and there's reason for concern. If the Tennessee-Louisville game is close, the fouling strategy down the stretch could have an enormous impact on which team advances.

No. 4 Washington State (Beat No. 13 Winthrop 71-40; No. 5 Notre Dame 61-41)
How they got here: The Cougs brought their meat grinder with them to Denver and chewed up the Eagles and Irish. After a sluggish first half against the Eagles which resulted in a 29-all tie at the half, the Cougs were dominating the rest of the weekend. They controlled tempo and took Irish star Luke Harangody (10 points, 3-for-17 shooting) completely out of the picture offensively.

Biggest strength: Defense. The Cougars have allowed a total of 52 points in their last game and a half, which is astounding. WSU was sixth in the nation in adjusted defensive efficiency, but the Cougars have taken things to a whole different level in the NCAAs. In their past 60 minutes of basketball, they are allowing an unheard of 0.56 points per possession. For perspective, Memphis led the country at 0.86. How big a difference is that? It's almost a point fewer allowed for every three possessions, which is huge.

Biggest problem: 3-point shooting. The Cougars have connected on only 8-of-30 from the arc in their two games. That's well below their season average of 37.5 percent. They're not going to be able to shackle explosive North Carolina like they have the Eagles and Irish. While the Tar Heels can be had at times defensively, the 3-ball will have to be a larger part of the equation if they hope to take out the 1-seed.

South Regional

No. 1 Memphis (Beat No. 16 Texas-Arlington 87-63; No. 8 Mississippi State 77-74)
How they got here: The Tigers cruised past Texas-Arlington and then fought off stubborn Mississippi State to win by three.

Biggest strength: Turnover differential. Memphis can look like a street-ball team at times with its DDM (dribble-drive motion) style and one-on-one inclinations, but the Tigers are remarkably careful with the ball for a team that plays that kind of style and at a fast tempo. Memphis only turns the ball over on 16.9 percent of its possessions, the 11th-best rate in the nation. They also force turnovers at a 22.3 percent clip, so they have a very positive turnover differential. Those extra possessions help cancel out the virtual turnovers they create when they miss free throws, making that issue less important against teams they can turn over. Michigan State was leaky this season overall, but has really tightened up the ballhandling in the past 10 games. The turnover battle in the Sweet 16 could decide the game.

Biggest weakness: Foul shooting. This one's a no-brainer. They're the second-worst team in all of Div. I. The problem has been harped on all season, it helped cost them the Tennessee game and their 15-for-32 effort Sunday against the Bulldogs made that game a lot closer than it needed to be. Given they will suffer from a significant free-throw deficit against almost any team they will face the rest of the way, Memphis probably has to be about eight points better than those teams in the rest of the game to keep advancing. That's a lot of pressure to put on a team that also doesn't shoot the 3 very well. Michigan State shoots 73.9 percent from the line and is one of the best offensive rebounding teams in the nation, meaning it might have a chance to get there a good amount against Memphis. If the Spartans can slow the tempo enough to shorten the game and avoid massive turnover issues, the Tigers could feel the free-throw squeeze.

No. 2 Texas (Beat No. 15 Austin Peay 74-54; No. 7 Miami 75-72)
How they got here: The Longhorns cruised past Austin Peay and then held off a furious rally from Miami in Round 2.

Biggest strength: Care with the ball. You'd never suspect a major-conference team would lead the nation in turnover rate, but the Longhorns are Div. I's most selfish team with the ball, coughing it up only 14.3 percent of the time. The Horns have only had one Div. I game all season in which that number was 20 percent or higher, so this isn't a fluke. Credit point guard D.J. Augustin for a large part of that, but you also have to have big men that can catch and make smart decisions with the ball, and the Horns have that, too. Damion James and Connor Atchley are extremely low-turnover bigs. Combine that stat with their extremely good offensive rebounding and you can see why they are one of the nation's elite offensive teams even though they are very average from inside the arc. Texas has scored at least 1.13 points per possession in each of its past five games, which is extremely good in league and NCAA tournament play.

Biggest weakness: Defensive rebounding. Like their next opponent, Stanford, the Longhorns don't force many turnovers on defense and instead focus on forcing bad shots. The difference between them and the Cardinal, though, is that Texas is a below-average defensive rebounding team, which when combined with the low turnover rate, helps opposing offenses get additional chances at the basket. While the Horns did a very good job on the defensive glass against Miami, Austin Peay grabbed 15 of them in the first round and the Governors certainly didn't have 14 feet worth of future NBA draft picks in their frontcourt like Stanford's Lopez twins. Stanford is the eighth-best offensive rebounding team in the land, so this is a huge area of concern for the Horns in the Sweet 16 matchup.

No. 3 Stanford (Beat No. 14 Cornell (77-53), No. 6 Marquette (82-81 OT)
How they got here: The Cardinal stifled Cornell and then escaped by the skin of their teeth against Marquette. Ejected head coach Trent Johnson missed seeing Brook Lopez's difficult baseline one-hander that rattled home with less than two seconds remaining in overtime to give Stanford a one-point win. He also missed point guard Mitch Johnson dish out 16 assists against just one turnover against the Golden Eagles.

Biggest strength: Lopez No. 2. Brook gets most of the buzz with his more polished offensive game, and his 30-point game against Marquette was huge in saving the Cardinal, but don't overlook Robin's vital contributions. In two NCAA tournament games, Robin is averaging 16.0 points, 6.5 rebounds and 4.0 blocks on a very efficient 14-for-19 shooting overall. He also draws the more difficult post assignments on defense and combines with Brook to provide a level of deterrence that allows the Cardinal's not overly athletic perimeter players to play tight, on-ball man defense without the fear of getting blown past off the dribble. They don't gamble and they steer traffic to the trees. Nice plan.

Biggest weakness: Not enough Anthony Goods. The Cardinal's third-leading scorer and best perimeter shooter has shot 5-of-17 combined in the two wins. However, the Cardinal are getting solid contributions off the bench from Taj Finger and Kenny Brown. That might not happen against Texas, though. The Longhorns are the most complete team Stanford will have seen and has one of the most efficient offenses in the land. If the Cardinal are to get past the Horns, you have to believe Goods will need to deliver the goods from the perimeter.

No. 5 Michigan State (Beat No. 12 Temple 72-61; No. 4 Pitt 65-54)
How they got here: The Spartans jumped ahead of both No. 12 Temple and No. 4 Pitt and then stayed steady down the stretch and beat both the Owls and Panthers by 11. They held both opponents under 40 percent shooting while Goran Suton and Drew Naymick combined for 33 rebounds in the two games.

Biggest strength: A wealth of dangerous perimeter players. Raymar Morgan and Chris Allen (off the bench) carried the Spartans with 27 combined points against Temple when Drew Neitzel and Kalin Lucas were struggling with their shots. Against Pitt, it was the exact opposite as Neitzel and Lucas combined for 40 points. That kind of offensive diversity from the guards is to be expected. Those four players are Michigan State's most frequent shot-takers in terms of the percentage of the team's shots they take while on the court. MSU has come to lean almost exclusively on them for offense, save for the occasional solid night from Suton. That might not be a bad recipe against top-seeded Memphis, which can devour post players but has given up some big games to explosive guards this season.

Biggest problem: Turnover differential. The Spartans had a negative turnover differential for the season and lost the turnover battle in each of their first two NCAA games (by one to Temple and by five to Pitt). The Tigers had one of the better turnover differentials in the nation, forcing them at a high rate and ranking 13th overall themselves, which is incredibly stingy given the style and pace they play. If the Spartans are going to slay the 1-seed, they can't give Memphis a bunch of extra possessions. The obvious problem there is it could create run-outs and easy baskets if the turnovers are not of the dead-ball variety. Either way, extra possessions would mean more margin for error for the Tigers if they have to overcome possible free-throw follies.

West Regional

No. 1 UCLA (Beat No. 16 Mississippi Valley State 70-29; No. 9 Texas A&M 51-49)
How they got here: The Bruins crushed the Delta Devils before almost meeting their maker against the Aggies. UCLA rallied from 10 points down in the second half and held off A&M courtesy of some huge shots from Kevin Love and Darren Collison and a couple of very questionable no-calls, including on the block of Donald Sloan's final shot attempt.

Biggest strength: Defense. MVSU was overmatched and A&M isn't the most explosive offensive team at times, but UCLA still completely throttled both teams' offenses. They combined to shoot just 35-for-117 (29.9 percent) from the field and 3-of-24 (12.5 percent) from the arc. The Bruins also defended without fouling (or at least being called); MVSU and A&M only shot 13 free throws combined. Surprisingly, A&M's offensive efficiency of 0.89 points per possession was above UCLA's schedule-adjusted season average, which shows you how slow the tempo in the second-round game was.

Biggest problem: Lack of complementary scoring. The Bruins only had three double-digit scorers combined in their two games. Getting next to nothing offensively from the power forward spot isn't unusual, because Luc Richard Mbah a Moute and Lorenzo Mata-Real are there for size and defense first. Six total points from Josh Shipp (zero against A&M), though, is a concern. He's the Bruins' primary 3-point shooter, and needs to provide something to complement Love, Collison and Russell Westbrook. Luck of the draw says they might be OK in the Sweet 16 game without a big contribution from Shipp, but he'll be needed after that.

No. 3 Xavier (Beat No. 14 Georgia 73-61; No. 6 Purdue 85-78)
How they got here: The Musketeers showed considerable resolve against Georgia, rallying from a double-digit deficit in the second half, before looking more like their A-10 champion selves against Purdue. The re-emergence of point guard Drew Lavender, seemingly finally heeled from an ankle injury, added an extra spark to the Xavier attack. Against the Big Ten's best field-goal percentage defense, Xavier shot 54 percent from the floor.

Biggest strengths: Balanced scoring and free-throw shooting. Neither should be a shock. Xavier's extreme scoring balance was a regular-season calling card and it was on display again against Purdue, when the X men had four players in double figures and two more with eight points apiece. In their first two NCAA games, they combined to shoot 53-of-66 (80.3 percent) from the stripe. That bodes well for the Musketeers if they have a late lead and could be a really important factor in the Sweet 16, when they face a West Virginia team that fouls a lot.

Biggest problem: Rebounding. The Musketeers have been outrebounded slightly in both games, which is a bit of a surprise given that they finished the season in the top 20 percent of Division I on both the offensive and defensive glass. Neither Georgia nor Purdue was a superior rebounding team, so it's something to watch, especially after seeing West Virginia destroy Duke on the glass.

No. 7 West Virginia (Beat No. 10 Arizona 75-65; No. 2 Duke 73-67)
How they got here: The two constants were leading scorers Joe Alexander (36 points, 19 rebounds in the two wins) and Alex Ruoff (38 points, 7-for-12 3s). Da'Sean Butler and Darris Nichols also had big nights against No. 10 Arizona, while No. 2 Duke felt the wrath of backup point guard Joe Mazzulla, who almost went for a triple-double.

Biggest strength: 3-point shooting. The Mountaineers went 11-for-19 against Arizona to bury the Wildcats. They weren't as prolific against Duke (just 4-for-11), but they made two timely ones, including Ruoff's fadeaway that beat the shot-clock buzzer and tied the game at 37, swinging the game's momentum. That's somewhat of a surprise, because the Eers didn't even finish in the top 100 nationally from the arc (35.9 percent as a team), although Ruoff is a 41.4 percent shooter. Equally shocking was the way WVU destroyed Duke on the glass. The Eers are a better rebounding team under Huggins and Duke isn't great on the boards, but a 47-27 rebounding advantage?

Biggest problem: Fouling. The Wildcats and Blue Devils combined to shoot 41-for-53 from the free-throw line, and neither team was padding its stats by trying to hold a late lead. This isn't an isolated issue, either. Playing Huggins' aggressive man-to-man, WVU finished 222nd in Div. I in opponent free-throw rate (FTAs per FGA). Xavier gets to the line a lot and is a very good free-throw-shooting team, so point differential at the line could be a big factor in the Sweet 16 game.

No. 12 Western Kentucky (Beat No. 5 Drake 101-99; No. 13 San Diego 72-63)
How they got here: The Toppers got the shot of the tournament so far, Ty Rogers' deep 3 that beat No. 5 Drake at the overtime buzzer, and then they held off No. 13 San Diego in a battle of first-round upset winners. Point guard Tyrone Brazelton delivered a monster game against the Bulldogs before the Toppers' best player, wing Courtney Lee, took over against the Toreros.

Biggest strength: The 3-ball. WKU has made 20 of 44 3s in its first two NCAA tournament games, a pace that seems sustainable given the team shot 39.0 percent this season, good for 26th in Div. I. What's more, the Toppers are not limited to one or two primary shooters. Five Hilltoppers took at least 75 3s this season and all of them are shooting at least 37.4 percent, with the two main marksmen, Brazelton and Lee, good for over 40 percent each. They'll have to attack UCLA somewhere, and from the arc seems a better bet than going inside and battling Kevin Love and Co.

Biggest problem: Defensive scheme has a ceiling. The Toppers thrived on turning teams over this season, finishing with the 13th-ranked defensive turnover rate in the nation. That said, the plan didn't hold up that well against the best teams they faced. Gonzaga (1.07 points per possession), Tennessee (1.15), Southern Illinois (1.32) and Drake (1.15) all had really good offensive days, in part because WKU puts teams on the free-throw line a ton. That doesn't bode well for its ability to stop a UCLA team that has two premier point guards to handle the ball, is really effective from inside the 3-point arc and shoots 73.4 percent from the line as a team.

Midwest Regional

No. 1 Kansas (Beat No. 16 Portland State 85-61; No. 9 UNLV 75-56)
How they got here: The Jayhawks cruised past Portland State and UNLV, not really being challenged in either game. Statistically speaking, that wasn't a surprise. Neither team was close to Kansas' caliber.

Biggest strength: Diversity of quality weapons. Kansas has shown its lethal depth in each of the first two games. The Jayhawks had five players with at least nine points against the Vikings and six with at least eight points against the Rebels. They're also shooting a searing 62-of-111 (55.9 percent) from the floor, including 17-of-38 (44.7 percent) from the arc. This level of performance conforms with Kansas' season-long offensive effectiveness. The Jayhawks had the most efficient offense in the nation at almost 1.19 points per possession and ranked in the top 10 in both 2-point and 3-point shooting. And outside of Darrell Arthur, the rest of the KU rotation players use roughly the same percentage of the team's possessions and take shots at similar rates. Even though Brandon Rush has evolved into the top scoring option, you can't key on any one player.

Biggest weakness: Fouling. The Jayhawks sent UNLV to the line 34 times in the second round. The Rebels made 27 of them, which helped them stay for awhile in a game in which they shot 12-of-45 from the field. KU has a tendency to put teams on the line a decent amount. In the Jayhawks' three losses this season, opponents went to the line 24, 28 and 27 times. None of the three victors (Kansas State, Texas and Oklahoma State) shot even 43 percent from the floor in the wins, so the free-throw production was pivotal. Why does this matter? Undersized Sweet 16 foe Villanova shoots 72.7 percent from the line.

No. 3 Wisconsin (Beat No. 14 Cal State Fullerton 71-56; No. 11 Kansas State 72-55)
How they got there: The Badgers did what the Badgers do, slowly stretching out leads and then shutting the door on frustrated foes who can't consistently crack the Badgers' defensive code. After solid starts, both Cal State Fullerton and Kansas State eventually tapped out. On offense, Wisconsin has solid balance inside and out and can get contributions from a variety of sources.

Biggest strength: The D. The Badgers led the nation in adjusted defensive efficiency and presented their calling card to the Titans and Wildcats in the form of two sub-40 percent shooting nights. Only eight times in 35 games this season have the Badgers even allowed an opponent to score one point per possession (the national average this season). Neither CSF or KSU came close in the NCAAs, and performances like that give the Badgers plenty of wiggle room to work through their own occasional offensive struggles. If the Badgers shoot 52.2 percent from the field like they did against K-State, it's lights out for just about any foe.

Biggest problem:
Style of next opponent? The Badgers' four losses this season (at Duke, Marquette, and a sweep by Purdue) all came against teams that were heavily guard-oriented. That could give surprise Sweet 16 foe Davidson some hope. If the Wildcats could hang with oversized Georgetown, can they find a way for Stephen Curry to squeeze some shots off while not getting hurt inside and on the glass? The more interesting theme in those losses was not that the small-ball teams shot particularly well. It's that Wisconsin had several very poor nights offensively against them.

No. 10 Davidson (Beat No. 7 Gonzaga 82-76; No. 2 Georgetown 74-70)
How they got here: The Wildcats rallied from double-digit second-half deficits against both Gonzaga and Georgetown, using two monster stanzas from star guard Stephen Curry and the support of a pro-Davidson crowd in Raleigh, N.C.

Biggest strength: They have the hottest player in the tournament. What more can you say about Curry, who backed up his 30-point second-half explosion against Gonzaga by pouring in 25 after the break against the shell-shocked Hoyas? He's scoring 35 points a game in the NCAAs. Imagine what he could do if he warmed up in the first half? The attention teams have to pay to Curry make the players around him more effective, but don't discount the talent of point guard Jason Richards, who led the nation in assists per game and had 35 points and 14 dimes in the two wins. The Wildcats are also getting standout play from rugged forward Andrew Lovedale, who's way over his season averages with a combined 23 points and 18 boards while holding down the interior. The fact that Curry also is a 90 percent free-throw shooter means the Cats can close out close games, which they did with aplomb against both the Zags and the Hoyas.

Biggest problem: Field-goal defense. The Wildcats have advanced despite allowing Gonzaga to shoot 50.9 percent and Georgetown to shoot a searing 63.4 percent. This isn't an isolated incident against top-caliber teams. North Carolina shot 46.2 percent, Duke shot 47.4 percent and UCLA shot 54.3 percent in Davidson's close high-profile nonconference losses. If the Wildcats can't find a way to ratchet that number down against Wisconsin, it could be a very tough evening at Ford Field. They haven't faced a defense as good as Wisconsin's yet this season and the Badgers now have two tapes worth of Curry explosions to study to find a way to slow him down.

No. 12 Villanova (Beat No. 5 Clemson 75-69; No. 13 Siena 84-72)
How they got here: The Wildcats rallied from 18 down to take out No. 5 Clemson and then jumped on No. 13 Siena early and confidently closed out the upstart Saints. As it always seems, good guard play has driven the Cats to their third Sweet 16 in four seasons.

Biggest strength: Sweet shooting (for now). For two games, the Wildcats have seared the nets, making an even 50 percent of their shots against Clemson and 53.6 percent against Siena. They've also connected on 13 of 26 3s in the two games. Can it last? This type of shooting is in direct contrast to Villanova's season performance, in which the Wildcats weren't even in the top half of Div. I in either 2-point or 3-point field-goal percentage. They probably can count on leading scorer Scottie Reynolds to carry the scoring load against Kansas, but will the Cats get enough from the supporting cast to threaten the Jayhawks? They'll have to, because this could be a huge mismatch inside with KU's terrific frontcourt depth.

Biggest problem: Fouling. The Wildcats were one of the 20 worst teams in Div. I in terms of defensive free-throw rate (opponents' foul shots as a percentage of field-goal attempts) and it hasn't gone much better in the NCAAs. They put Siena on the foul line a whopping 39 times on Sunday and allowed 23 against Clemson. The Tigers are so bad at the line, that might have been a good thing, and Siena was so far behind most of the day that it didn't really impact the result. KU shoots over 70 percent from the line as a team, so that MO probably won't go over so well on Friday. Fouls also equal foul trouble and the Wildcats don't have the depth, especially in the frontcourt, to deal with Kansas that way.

[Editor's note: Season stats and rankings courtesy of kenpom.com]

Andy Glockner is a regular contributor to ESPN.com's college basketball coverage and is the host of the ESPNU College Basketball Insider podcast. He can be reached at bubblewatch@gmail.com.