Late Saturday afternoon and into the evening, the Big Ten's East Division race began to come into clearer focus. Not at the top, where Ohio State staved off the Gophers' upset bid, but just below, where some surprising shifts were taking place.

In State College, Pa., Penn State — which had a week off to recover from its come-from-ahead, 27-26 loss to Ohio State — found a way to let Michigan State hang around just enough for the Spartans to escape with a 21-17 victory on a 25-yard touchdown pass from Brian Lewerke to Felton Davis with 19 seconds left in the game.

Fast forward to later that night in Ann Arbor, where Michigan faced West-leading Wisconsin in basically an elimination game when it came to College Football Playoff hopes.

Both teams carried one loss into the game, and after the Wolverines dismantled the Badgers 38-13, Wisconsin limped home with a promising season in tatters.

That left us with No. 2 Ohio State (7-0, 4-0 Big Ten), No. 6 Michigan (6-1, 4-0), No. 24 Michigan State (4-1, 2-1) and Maryland (4-2, 2-1) as contenders for the East title. And on Saturday, all eyes will be on the East again with this matchup:

Michigan at Michigan State.

"The way it always has been, the way it is, the way it always will be," Wolverines coach Jim Harbaugh said, using his usual economy of words. "Big game."

It's especially big for Michigan and Harbaugh, who has posted 10-3, 10-3 and 8-5 records in his three previous seasons at his alma mater, not exactly a big return on his annual $7.5 million salary. Since the Big Ten split into divisions in 2011 and implemented a championship game, the Wolverines have yet to play in it.

"Improvement will lead to success, will lead to championships," Harbaugh said.

The Spartans have been a thorn in Michigan's side for the past decade, with victories in four of the past five games and eight of the past 10. Though the Wolverines won the last meeting in East Lansing, 32-23 in 2016, few can forget the 2015 finish, when Michigan punter Blake O'Neill fumbled a snap and the Spartans returned it for a touchdown and a 27-23 victory on the game's last play.

"It's good for college football and I also think it's also good for the state of Michigan," Spartans coach Mark Dantonio said of the rivalry, in which he is 8-3 against Michigan.

"Everybody's enthused."

That's the case with Michigan, which has recovered from its 24-17 loss at Notre Dame in the season opener to win six in a row and not allow an opponent to score more than 21 points. The Wolverines are giving up 238 yards per game, second fewest in the country, and only 209.3 in Big Ten play.

Their dominance was on display against Wisconsin. When Michigan's Lavert Hill intercepted an Alex Hornibrook pass and returned it 21 yards for a touchdown and 31-7 Wolverines lead with 9:55 left in the fourth quarter, the Badgers QB had more than double the yardage in interception returns surrendered (52) than he had in passing yards (25, on 3-for-11 passing).

Michigan State, meanwhile, is no slouch on defense, either. The Spartans are allowing 62.3 rushing yards per game, fewest in the country. They will need that against a Michigan offense that ran for 320 against Wisconsin.

It all adds up to an intrastate rivalry with conference and national implications.

"If you can play well in October, then you're going to be in the hunt for things in November," Dantonio said. "So that's our intent as we move forward, but yeah, I think [the rivalry] intensifies things."

Randy Johnson covers college football for the Star Tribune. Twitter: @RJStrib. E-mail: rjohnson@startribune.com