What did we learn in the ACC in Week 4? Glad you asked.

1. Clemson is not perfect: The way Clemson won on Thursday night at NC State will not win the Tigers any beauty contests. They were sluggish on offense for most of the game, and nobody could quite figure out why afterward. Was it the long layoff between games against FBS teams? Was it more a product of NC State harassing Tajh Boyd? Were they playing too tight and not relaxed? Clemson finally got a few drives going in the second half (thanks to a call that may or may not have been botched) but the offense still needs some work. The defense, meanwhile, has made huge strides. Coaches thought this front seven could be good, and it was strong against the Wolfpack. But what stood out most of all was the way Clemson was able to overcome its mediocre play and win. That might not have happened two years ago.

2. Georgia Tech is in good shape: Say this for the Yellow Jackets, they came into the season relatively under the radar but have played themselves into the Coastal conversation after a 2-0 start in division play. It is the second time under Paul Johnson that Georgia Tech has started Coastal play 2-0 (it also happened in 2011), but just the third time in the past 15 years it has won its first two league games. Georgia Tech has now won six straight regular-season ACC games dating back to last season, tied for the second-longest league winning streak in school history. Without question, this is the toughest stretch of the season for the Jackets, and if they can keep this up, they will be in the driver’s seat to get back to the ACC title game. Next up is a Virginia Tech team that needed three overtimes to beat Marshall on short rest Thursday in Atlanta. Given the way the Hokies looked on Saturday, there is a decent chance Georgia Tech and Miami will be undefeated when the two teams play in Miami on Oct. 5. But it’s too early to look ahead. To beat Virginia Tech, the Jackets are going to need a lot more consistency on offense than they got in their win over North Carolina.

3. Virginia Tech D is not perfect: The Hokies went into the game with the No. 2 ranked defense in the entire nation, but they did not play that way in the first half against Marshall, giving up 21 points and 205 yards while staring at a deficit. Virginia Tech had a much harder time slowing down the hurry-up offense Marshall runs. I called this group the “hands down best defense” in the ACC but that title appears to be up for grabs right now. Virginia Tech did regain its composure in the second half and allowed just 156 yards the rest of the way, with two interceptions and a fumble recovery. But this was the most uneven performance out of this group this year. You have to wonder how much the struggles of the offense are going to start taking its toll on the defense.

4. The ACC could have another Top 25 team: When the polls are released later today, the big question is whether Georgia Tech or Maryland (maybe both?) will be ranked for the first time this season. The ACC has five unbeaten teams to this point, a great accomplishment for a league that has struggled to change its national reputation. Maryland (4-0) completely embarrassed West Virginia in all facets, winning 37-0 while holding the Mountaineers to six first downs and 175 yards of total offense. Maryland has not beaten anybody with a winning record yet (Week 1 opponent FIU just lost 72-0 to Louisville), so its undefeated start is not wildly unexpected. Still, it is quite an achievement for a program that has won six total games over the past two seasons.

5. Pittsburgh and Duke could use some defensive help: Both teams went into the season with high expectations for their respective groups. Pitt had a veteran group returning; Duke believed it had made strides from a unit that crumbled in the second half of 2012. Neither one showed much progress in a 58-55 Pitt win. The early results we saw from the Duke defense have been put into perspective now that the Blue Devils have played better teams in Georgia Tech and Pitt. The Blue Devils had a hard time getting off blocks Saturday, Blue Devils coach David Cutcliffe said. To make matters worse, linebacker Kelby Brown got hurt. Pitt is a team that clearly misses defensive coordinator Dave Huxtable. That was made more apparent after watching his game plan to slow down Boyd and Clemson in his new job as NC State defensive coordinator. Pitt has given up 123 points in three games. If it can get a defense to pair with what looks like a solid offense, watch out.