This week's Power Rankings feature a new No. 1, as last week's No. 1 takes a tumble:
1. Oklahoma (4-0, 1-0 Big 12, last week 3): The Sooners take over the top spot after delivering the most impressive Big 12 win of the season. Notre Dame is not the same team as last season, but the Irish hadn't lost in South Bend since October of 2011. OU has been a different team since Blake Bell took over at quarterback, and Bell was fabulous Saturday, throwing for two touchdowns without a turnover while churning out first downs with his arm and his legs. The OU defense is clearly better, too, picking off QB Tommy Rees on Notre Dame's first two possessions, with linebacker Corey Nelson returning one for a touchdown. The Sooners were clearly a team overlooked in the preseason, and, after five weeks, are looking like a clear Big 12 favorite along with Baylor.
2. Baylor (3-0, 0-0 Big 12, last week 2): After the off week, the Bears' offense will get its first real challenge this weekend from West Virginia's defense that appears to be the most improved unit in the league. Baylor has been unstoppable so far, but the level of competition is about to undergo an uptick. Can the Bears keep it up? They've shown no signs they can't.
3. Texas Tech (4-0, 1-0 Big 12, last week 4): Despite having the week off, the Red Raiders move up a spot with Oklahoma State's loss. The big question in Lubbock is who will be starting at quarterback for Tech come Saturday against Kansas. Baker Mayfield? Davis Webb? Michael Brewer, who has been progressing well from the back injury? The Red Raiders have been solid defensively, and the skill talent is legit. If Tech can get better play from its quarterback, this team could be a handful -- even for OU and Baylor.
4. West Virginia (3-2, 1-1 Big 12, last week 8): What a difference a week makes. The Mountaineers produced the most impressive in-conference win of the season with a 30-21 victory over preseason favorite Oklahoma State. West Virginia's defense continues to play at a high level (Maryland's 37 points were somewhat of an anomaly because of West Virginia turnovers) and Clint Trickett sparked the offense with his energy and leadership. West Virginia's offense is still pretty limited, but at least it no longer looks completely inept with Trickett at quarterback. The Mountaineers can't score with Baylor this weekend, but maybe they can slow the Bears down? Nobody thought West Virginia could slow Oklahoma or Oklahoma State, either, though Baylor's offense is at another level. We'll see.
5. Texas (2-2, 1-0 Big 12, last week 5): The Longhorns have a couple of interesting games looming. Thursday, Texas travels to Iowa State, which looked much better offensively in a 38-21 win at Tulsa this past Thursday. Then, Texas gets surging Oklahoma in Dallas. This figures to be the defining two-game stretch of the season for the Longhorns. Win the next two, and the season -- as well as Mack Brown's status in Austin -- looks totally different than it did two weeks ago. The off week could not have come at a better time for the Longhorns, giving acting defensive coordinator Greg Robinson another week to acclimate to his defense and quarterback David Ash another week to recover from the head injury that knocked him out of the Ole Miss and Kansas State games.
6. TCU (2-2, 0-1 Big 12, last week 6): Did TCU's offense finally uncover an identity during a rainy fourth quarter against SMU? The Horned Frogs poured on 31 points in the final quarter and did it with some new faces, as Ty Slanina, Ja'Juan Story and Cameron Echols-Luper all factored into the scoring onslaught in the first real action of their TCU careers. The Horned Frogs can really turn their season around with a win in Norman this weekend. That won't be easy, though, if All-American cornerback Jason Verrett (shoulder) and defensive end Devonte Fields (foot) can't play.
7. Oklahoma State (3-1, 0-1 Big 12, last week 1): The Cowboys plummet six spots after an uninspiring performance in Morgantown. It was just one loss, but it was a loss that exposed weaknesses across the board. For the first time in seemingly forever, Oklahoma State's kicking game is awful. The Cowboys' secondary gave up 320 yards to a West Virginia passing attack that previously had been completely futile. And on the other side of the ball, when the Mountaineers dared QB J.W. Walsh to beat them deep, he couldn't do it. That allowed West Virginia to stuff the Cowboys' running game, which also doesn't appear to have that bell-cow running back Oklahoma State has been accustomed to featuring. The Cowboys are better than they looked at West Virginia -- but how much better?
8. Kansas State (2-2, 0-1 Big 12, last week 7): Bill Snyder maintains the Wildcats will stick with the two-quarterback system, which has yielded mixed results. K-State has moved the ball better when Daniel Sams has been in at quarterback. But when he's in, the Wildcats are virtually no threat to pass. Sams has 29 rushes and only four passing attempts. Is Sams really that poor of a passer? Maybe it's time for K-State to find out.
9. Iowa State (1-2, 0-0 Big 12, last week 10): It's hard to believe a center could make that much of a difference. But the return of Tom Farniok sure seemed to do wonders for Iowa State's offense, which finally got going in a 38-21 win at Tulsa. The Cyclones also finally involved running back Aaron Wimberly, who ignited the running game with Iowa State's first 100-yard performance in more than a year. With former blue-chip junior-college transfer E.J. Bibbs emerging now at tight end, QB Sam Richardson no longer appears to be on his own. Jack Trice will be rocking Thursday night for the Longhorns, as Iowa State has a chance to land a signature win to build off of for the rest of the season.
10. Kansas (2-1, 0-0 Big 12, last week 9): The Jayhawks have a winning record but have been mostly unimpressive. Can they turn around the offense against Texas Tech? That will hinge almost entirely on quarterback Jake Heaps, who has talent but has been unable to find any rhythm so far with a collection of unproven wideouts. If the Jayhawks can be competitive this weekend, it will be a good sign they are moving in the right direction. If they get blasted, it could be a long season, especially with Iowa State and West Virginia seemingly having found their stride.