Once upon a time, in the not-so-distant past, Michigan State was Ohio State's toughest Big Ten opponent.

But in recent years, the Spartans have fallen on hard times, and the Buckeyes have dominated them under Ryan Day.

On Saturday night, a prime-time game in name only, No. 1 Ohio State rolled to a 38-3 victory in front of 105,137 at Ohio Stadium after scoring five first-half touchdowns.

The Buckeyes improved to 10-0 (7-0 Big Ten), with only their home finale against Minnesota next week left before their long-awaited showdown with Michigan.

Michigan State, which endured the suspension and then firing of coach Mel Tucker early in the season following sexual harassment allegations, fell to 3-7 (1-6 Big Ten).

Ohio State was a 32½-point favorite, and the Buckeyes nearly covered that by halftime. They scored touchdowns on five of their first six possessions and their defense allowed only a 53-yard field goal.

Ohio State quarterback Kyle McCord was nearly flawless. The junior completed 24 of 31 passes for a career-high 335 yards and three touchdowns.

Two of them went to Marvin Harrison Jr., whose ticket to New York as a Heisman Trophy finalist almost certainly has been punched. Playing only 2½ quarters before resting, Harrison caught seven passes for 149 yards to become the first Buckeye to have two 1,000-yard receiving seasons.

"Being the first ever to do something in Ohio State history, especially as a receiver with all the great receivers who've come through this place, that means a lot," Harrison said.

Cade Stover returned after missing last week's game at Rutgers and caught seven passes for 79 yards and a touchdown with 15 seconds left in the first half to give OSU a 35-3 lead.

It was the first time since early in the season that Ohio State had its full complement of skill-position players.

"We're getting all of our pieces back," Day said, "and I think you're starting to see our identity start to forge a little bit, what we're doing on offense. Some (years), it takes a little bit longer to figure that out. You're seeing us play with more and more confidence."

Harrison opened the scoring with the first rushing touchdown of his career. He took a handoff on a reverse and ran 19 yards into the end zone.

"I think we've called that play three times in my career, and came up short the other two times," Harrison said. "I finally got to the end zone, so it's definitely a special one for me."

Harrison made it 14-0 when he made a nifty catch near the sideline of a perfect McCord pass for a 26-yard touchdown.

The high school teammates at St. Joseph's Prep in Philadelphia hooked up again on the first play of the second quarter on a 10-yard touchdown.

TreVeyon Henderson scored on a 9-yard carry set up by a 30-yard reception by Xavier Johnson to put Ohio State ahead 28-3. Henderson finished with 63 yards in 13 carries.

Stover's touchdown catch ensured that the second half would be only a formality.

Ohio State had 20 first downs in the first half and gained 360 yards.

The Buckeyes' defense wasn't quite as dominant as their offense, but it was plenty good enough, especially considering it was without three injured starters. The unit played without its leader, linebacker Tommy Eichenberg, as well as safeties Josh Proctor and Lathan Ransom.

Day said Eichenberg and Proctor are shorter-term injuries, but Ransom's is more long-term.

The Buckeyes got better as the game wore on. They didn't force a three-and-out until Michigan State's fifth possession, but in the final three quarters, the Spartans averaged only 2.6 yards per play. Michigan State never got past the OSU 34-yard line.

"Missing Tommy leaves a big hole in our defense," linebacker Cody Simon said, "but our job is to step in and fill that hill."

Ohio State still has not allowed an opponent to score more than 17 points, even if getting a shutout has been elusive.

The only points of the second half came when Jayden Fielding kicked a 36-yard field goal set up by a 57-yard catch by Harrison. At that point, McCord had completed 22 of 26 passes.

Backups played most of the final two quarters. Henerson and Stover didn't play at all in the second half, and Harrison and Emeka Egbuka played only on the first possession of the third quarter.

"This has been quite a run for us," Day said. "It was good to get those guys out of the game and cut their numbers (of snaps) down because we know where we need to be here."

Get more Ohio State football coverage by listening to our podcasts

This article originally appeared on The Columbus Dispatch: Marvin Harrison Jr., Ohio State click in rout of Michigan State