Posted by ESPN.com's Adam Rittenberg

Five lessons from the week that was in the Big Ten.

1. Spartans have new life -- Michigan State couldn't have scripted a better way to breathe new life into its season. Mark Dantonio's team overcame a fourth-quarter collapse against archrival Michigan to prevail in overtime. Most important, the Spartans did it with defense, as a veteran-laden unit finally played to its potential and held the Big Ten's best rushing attack to only 28 yards. Quarterbacks Kirk Cousins and Keith Nichol played well when they had to, and freshman running back Larry Caper came through with the game-winning scoring run. It was an emotional win after three tough losses as Michigan State beat Michigan in consecutive seasons for the first time since 1965-67.

2. Wisconsin is in the league title mix -- After an extremely disappointing 2008 season, Wisconsin is off to a 5-0 start and showing improvement on both sides of the ball. The Badgers overpowered Minnesota after halftime with running back John Clay (184 rush yards, 3 TDs) and continued to get great performances from senior defensive end O'Brien Schofield (3.5 tackles for loss, two sacks, forced fumble). They still struggle to close games, but they're extremely opportunistic and consistently make opponents pay for mistakes. Wisconsin can further validate its start by upsetting Ohio State next week in Columbus.

3. Penn State can run the ball -- The biggest question for the Nittany Lions was answered Saturday, as a new-look offensive line overpowered Illinois in the second half. The line created running room for quarterback Daryll Clark, who had a nice rebound performance, and for running backs Stephfon Green and Evan Royster, who both eclipsed 100 rush yards. Granted, Illinois might be the worst team in the league, but 338 rushing yards on the road shouldn't be discounted. With Penn State's defense getting healthier, it was a very good sign.

4. Defense wins in this league -- Quarterback play has been mediocre throughout the Big Ten this season, while opportunistic defenses have risen to the occasion. Both Michigan State and Northwestern received big performances from veteran-laden defenses that struggled, and both Ohio State and Penn State turned in dominant defensive performances on the road. Iowa had an ugly win over Arkansas State, but the Hawkeyes defense extended its incredible streak of no rushing touchdowns allowed to 33 quarters.

5. As Tate Forcier goes, so does Michigan -- Forcier has already saved the Wolverines several times in his young career, and he nearly pulled off another magic trick in East Lansing. As it turned out, his interception in overtime helped Michigan State prevail. As good as Forcier has been, Michigan needs to be able to win games in different ways. Iowa represents a very tough test next week, and Forcier will have all he can handle with the Hawkeyes' defensive front. I wouldn't bet against Forcier in the clutch, but Michigan still must improve on defense and get more production from its deep group of running backs.