Big Ten power rankings: Week 13

The top spot in the Big Ten power rankings was a shaky place to be during the past month or so. But Michigan State broke the trend Saturday, affirming itself as the league's No. 1 team with a dominating performance.

Michigan also makes a move after its best effort of the season, while Nebraska and Purdue both take tumbles.

Let's get to the rankings.

1. Michigan State (9-2, 6-1 Big Ten): Mark Dantonio's squad left no doubt about the best team in the Legends Division, punching its ticket to Indianapolis with a 55-3 thrashing of Indiana on Senior Day. Kirk Cousins and his fellow seniors stepped up in their final home game, and the Spartans now have won three straight. It will be interesting to see how Michigan State approaches this week's game at Northwestern, as the division is already in hand. The Spartans will face Penn State or Wisconsin in Indy.

2. Wisconsin (9-2, 5-2): After a very sluggish first half, Wisconsin got its act together behind "Moneyball" and an opportunistic defense that recorded four takeaways in the final 30 minutes. Montee Ball became the fifth player in FBS history to record 30 touchdowns in a season, and he had a huge second half in putting himself on the Heisman Trophy radar. Wisconsin will need a cleaner performance on both sides this week against Penn State, although the Badgers have been unshakable at home.

3. Michigan (9-2, 5-2): Michigan notched a long-awaited signature win with a signature performance Saturday against Nebraska. Denard Robinson and Fitzgerald Toussaint both had huge performances, combining for six touchdowns, and an ever-improving defense recorded three takeaways. Although Michigan's win handed the division title to rival Michigan State, it keeps the Wolverines in the mix for an at-large BCS berth, which looks like a stronger possibility than it did a week ago.

4. Penn State (9-2, 5-1): After two nightmarish weeks, Penn State finally got to celebrate a well-earned victory against Ohio State. Interim coach Tom Bradley and his staff employed an aggressive game plan that included the Wildcat formation on offense, which Curtis Drake and Bill Belton executed effectively. The coaches will need a few more wrinkles in this week's game plan as Penn State visits Wisconsin in what amounts to the Leaders Division championship.

5. Nebraska (8-3, 4-3): What a buzzkill. Nebraska had plenty to play for Saturday at Michigan but imploded in the second half and suffered its second humiliating road loss of the season. The Huskers had turnovers, penalties, blown coverages and poor protection in a miserable performance. While Nebraska has done some nice things this season, Big Red clearly hasn't arrived in the Big Ten. The Huskers return home this week to face Iowa in a game that should determine bowl position.

6. Iowa (7-4, 4-3): It wasn't pretty, but Iowa finally notched a road win after failing on its first three opportunities. The Hawkeyes received big performances from their big three -- QB James Vandenberg, RB Marcus Coker and WR Marvin McNutt -- and pulled away from Purdue in the second half. Although Iowa needs to cut down on its turnovers and penalties this week at Nebraska, the Hawkeyes' offense should be able to score in Lincoln.

7. Northwestern (6-5, 3-4): Credit Pat Fitzgerald's crew for not giving up after a five-game slide from mid-September until late October. Northwestern has rattled off four consecutive wins to become bowl eligible for the fifth consecutive year. A much-maligned defense has made strides during the past three games, allowing just 44 points. Northwestern can assure itself of a bowl spot by beating Michigan State this week in Evanston.

8. Ohio State (6-5, 3-4): It's pretty clear the Buckeyes reached their peak against Wisconsin on Oct. 29. They haven't been the same team since, falling behind early in each of their last three games and losing to both Purdue and Penn State. The offense suffers from inexperience and lack of creativity, and the defense misses too many tackles and assignments. The Penn State game showed all you needed to know about the 2011 Buckeyes. All that's left is a chance to extend the win streak against Michigan.

9. Purdue (5-6, 3-4): After a one-week rise up the rankings, the Boilers backslid because of their inability to sustain success. Purdue has followed all five of its wins this season with a loss, the latest a mistake-filled performance against Iowa. The Boilers committed four turnovers and racked up only 282 yards, certainly not the performance they needed at home after the Ohio State triumph. Purdue now must beat rival Indiana to get bowl eligible for the first time since 2007.

10. Illinois (6-5, 2-5): The Illini showed up in the first half and dominated Wisconsin, setting up a potential season-saving upset. But once again, Illinois endured a miserable stretch, this time in the second half as it committed turnovers on three of four possessions. Illinois handed Wisconsin the game and dropped its fifth straight, adding fuel to the fire around embattled coach Ron Zook. The Illini might need a win this week at Minnesota to claim a bowl spot.

11. Minnesota (2-9, 1-6): After a rough start in Evanston, the Gophers put themselves within striking distance. But two second-half turnovers really stung, and the offense never found a consistent flow against Northwestern. Minnesota never got close enough to scare the Wildcats and made too many mistakes (turnovers, dropped passes) to win. Jerry Kill's crew can finish a rough season on a good note as it hosts slumping Illinois on Saturday.

12. Indiana (1-10, 0-7): This season can't end soon enough for Indiana, which suffered its second 52-point loss of the season. The open week clearly didn't help the Hoosiers, who allowed 48 points in the first three quarters and never established a groove on offense. There's so much work to do on defense, and freshman QB Tre Roberson had a rough outing with two interceptions. The only thing left is an opportunity to prevent rival Purdue from becoming bowl eligible this week in Bloomington.