Ohio State’s explosive offense, starring Big Ten Player of the Year quarterback Justin Fields, made headlines all season. But the Buckeyes had to rely on defense and a spectacular performance from a new offensive standout in Saturday’s B1G Championship Game in Indianapolis.

Ohio State, 4th in the College Football Playoff rankings, won its 4th straight conference championship and almost certainly clinched a CFP semifinal berth with a 22-10 victory over a strong Northwestern team Saturday. Buckeyes graduate transfer running back Trey Sermon broke the all-time Ohio State rushing record for a single game with 331 yards on the ground.

OSU’s spot in the CFP left No. 5 Texas A&M hoping for help elsewhere, though the Buckeyes rally certainly dimmed the Aggies’ Playoff hopes.

Sermon also had the best rushing performance in B1G title game history; he had 2 touchdowns as well. He had a 65-yard run in the third quarter and a go-ahead touchdown on another third-quarter drive. In his lone season at OSU after transferring from Oklahoma, Sermon mostly had a secondary role behind Master Teague this season, gaining 333 rushing yards and 1 touchdown on 55 carries in 5 games coming into Saturday.

And the OSU defense came up with three second-half turnovers to stifle a Northwestern offense that had a strong first half.

With six all-conference first-team selections by coaches’ voting, including receivers Garrett Wilson and Chris Olave plus 3 linemen, the Buckeyes came into Saturday’s Big Ten Championship Game averaging 46.6 points per game, 4th in the nation. But Fields was off his game all day and had the thumb on his right (throwing) hand taped in the second half. Fields was just 12-of-17 for 114 yards, 2 interceptions and no touchdowns.

After Sermon’s 9-yard touchdown run put Ohio State ahead 13-10 late in the third quarter, junior safety Josh Proctor intercepted Northwestern’s Peyton Ramsey on the ensuing drive. OSU backup punter Zach Hoover pinned the Wildcats at the 5-yard line (the second time he put Northwestern deep in its own territory). OSU got the ball back after a Wildcats punt and drove for Blake Haubeil’s third field goal of the day, a 26-yarder, for a 16-10 lead with 12:07 left in the game.

Sermon’s 3-yard TD run with 4:03 left put OSU ahead 22-10, capping a second half when OSU dominated with its running game, especially Sermon.

No. 14 Northwestern led for most of the first half and well into the third quarter.

OSU linebacker Justin Hilliard intercepted Ramsey in the end zone to end NU’s first drive of the second half. But Wildcats defensive back Cameron Mitchell picked off Fields quickly on the next drive, the second interception of the game for Fields.

In the first half, Fields was just 9-of-19 for 95 yards and Wildcats defensive back Brandon Joseph, the B1G’s freshman Defensive Player of the Year, made a leaping one-handed interception to ruin OSU’s best drive of the half. The Buckeyes reached the Wildcats 9-yard line but Fields, trying to find Wilson in the end zone, was picked off by Joseph.

After starting a drive early in the second quarter at its 6-yard line, NU moved the ball down to the OSU 23-yard line but went backward on a third-down screen pass. The Wildcats settled for Charlie Kuhbander’s 47-yard field goal and a 10-3 lead.

Haubeil’s 43-yard field goal with 5:23 left in the first half brought OSU within 10-6, capping a 7-play, 49-yard drive. Haubeil missed a 42-yarder wide left in the middle of the third quarter.

In the first quarter, Ramsey’s 34-yard run up the middle set up Cam Porter’s 9-yard touchdown run on the next play to give Northwestern a 7-3 lead with 4:02 left.

Earlier, Cameron Mitchell and Chris Bergin sacked Fields on third down as Northwestern held OSU to a 42-yard field goal by Haubeil on the first Buckeyes drive. It was the only time in six games this season that OSU failed to score a touchdown on its opening drive.

The Buckeyes were missing 22 players including WRs Chris Olave and Jaxon Smith-Njigba, LB Baron Browning and P Drue Chrisman. Assistant coaches Brian Hartline (receivers) and AL Washington (LBs) were also absent. For Northwestern, all-conference DB Greg Newsome left in the first half with an apparent injury.

True freshman receiver Julian Fleming, OSU’s No. 1 recruit from the Class of 2019, started and had three catches on the Buckeyes’ first drive. That matched his production for the entire season coming into the game.

OSU had trailed for just 5:05 the entire season (all early in the opener against Nebraska) coming into Saturday.