Michigan State just never stopped fighting.

In a massive top-10 matchup against in-state rival No. 6 Michigan, No. 8 Michigan State trailed 30-14 midway through the third. But Mel Tucker’s Spartans would not wilt.

Behind a Heisman-worthy five-touchdown performance from Kenneth Walker III, Michigan State stormed all the way back and emerged with a thrilling 37-33 victory in front of its home fans in East Lansing.

Walker, the transfer from Wake Forest, had a few moments early but could not be stopped in the second half. Walker scored from a yard out late in the third, exploded for a 58-yard score early in the fourth and burst through the line for what ended up being the game-winning 23-yard touchdown with 5:08 to go.

Walker finished the afternoon with 197 yards on 23 carries and five scores, helping the Spartans improve to 8-0 and maintain their positions near the top of both the Big Ten and College Football Playoff races.

Michigan used passing game to jump out to big lead

The way Michigan’s offense was moving the ball early made Michigan State’s comeback even more remarkable. Entering Saturday’s game, the Wolverines overwhelmingly relied on their running game. In this one, the Michigan offensive staff flipped the script and went to the air.

Michigan QB Cade McNamara was averaging just 20.8 passing attempts per game to this point in the year, but he was tearing up the MSU secondary early on. He hit little-used freshman Andrel Anthony for a 93-yard touchdown to give Michigan an early 7-0 lead. Anthony caught a second touchdown, this time from J.J. McCarthy, later in the first half to help UM add to its lead.

Michigan, though, would stall in the red zone and settle for a few short field goals. Michigan’s halftime lead was 23-14, but it felt more lopsided than that.

Fourth-down completion, 2-point conversions key to MSU comeback

Michigan added to its lead and made 30-14 with 6:47 left in the third. On the ensuing drive, Michigan State moved into Michigan territory and faced a do-or-die fourth-down play.

On fourth-and-4 from the Michigan 29, Payton Thorne dropped one in to Jayden Reed for a 28-yard gain down to the Michigan 1-yard line.

On the next play, Walker scored to cut it to 30-20. That’s when Tucker made a pivotal decision and kept his offense on the field for a two-point conversion to cut the Michigan lead to just one possession. Some coaches might have attempted the extra point, thinking it was too early in the game to "chase points."

Tucker sided with the analytics and the conversion was successful, the score was 30-22, and all of a sudden Michigan was no longer firmly in control of the game.

From there, the Spartans would not stop attacking. They quickly forced a Michigan punt on the ensuing possession, setting up Walker’s 58-yard touchdown that would tie the game.

Walker’s touchdown came on a third-and-3 play. Before that drive, the Spartans were 0-of-7 on third down. On that drive, MSU converted three straight third downs, including Walker’s scamper from 58 yards out that tied the game at 30-30 after another successful two-point try.

Michigan would go ahead with a field goal on the next drive, but the Spartans would ultimately take the lead for good with 5:08 to go after the first turnover of the game by Michigan.

As they have throughout the season, the Wolverines rotated McCarthy in at quarterback throughout the ballgame, and he had a botched exchange with a running back. Michigan State would recover in Michigan territory.

Seven plays later, Walker would score again to put the bow on a momentous day in East Lansing.

What does this mean for Michigan State?

Michigan State is now 8-0, making it the lone unbeaten in the Big Ten and one of just eight undefeated teams remaining in the country.

From both a Big Ten championship and College Football Playoff perspective, it's hard not to look ahead to a looming matchup with Ohio State on Nov. 20. OSU lost a non-conference game to Oregon in Week 2, but has been blowing out every team it has faced since then.

Before the Spartans travel to Columbus, however, they will go to Purdue next weekend and host Maryland on Nov. 13. If both the Spartans and Buckeyes keep winning, that matchup on the 20th could serve as the de facto Big Ten East title game.

What about Michigan?

This is a brutal turn of events for Michigan, which has had no shortage of tough losses in marquee games during Jim Harbaugh's tenure. Like Michigan State, Michigan entered the day with a 7-0 record and a clear path to both the Big Ten title and College Football Playoff. Those paths are much less clear now.

And from a big-picture perspective, it's just the latest in a lengthening list of shortcomings under Harbaugh. The Wolverines have bounced back nicely from last season's debacle, but are now 2-13 vs. top 10 opponents under Harbaugh and a 3-9 combined against Ohio State and Michigan State.

Harbaugh is also 0-2 against Tucker, who inherited what was looked at as a big rebuild in East Lansing. Instead, he has Michigan State on the precipice of accomplishments Michigan has not been able to reach in seven years under Harbaugh.

For Michigan fans, that's a tough pill to swallow.