No. 1 Ohio State took several roundhouse punches from No. 8 Wisconsin in the first half but shut out the Badgers in the second half while scoring 27 points, including two touchdown catches by K.J. Hill.

INDIANAPOLIS — Everything was going wrong.

The juggernaut that No. 1 Ohio State had been all season was nowhere to be found for the first 30 minutes Saturday night of the Big Ten championship game against No. 8 Wisconsin.

The defense couldn’t tackle Badgers star running back Jonathan Taylor and couldn’t contain quarterback Jack Coan.

The offense was no better. Justin Fields, playing with a brace to protect a sprained left knee and having had limited reps in practice, was out of sync on throws and lost a fumble inside the Wisconsin 10-yard line.

Defensive end Chase Young, who had four sacks in a 31-point victory over Wisconsin in October, was held in check. Standout cornerback Jeff Okudah sat on the bench without a helmet because of concern he’d sustained a concussion.

A Buckeyes touchdown with 42 seconds left before halftime was answered, stunningly, by a Badgers one 32 seconds later for a two-touchdown Wisconsin lead at halftime.

For Ohio State, the moment of truth had arrived. The Buckeyes’ spot in the College Football Playoff wasn’t really at risk, but certainly their chance to retain the No. 1 ranking was.

That’s what made Ohio State’s second-half dominance in a 34-21 victory in front of a Buckeye-dominated crowd at Lucas Oil Stadium so important.

“I think you’ve seen our talent, our execution, a lot of things,” coach Ryan Day said. “But today showed our team’s heart. I think that’s what makes this the best win of the year.”

Ohio State (13-0) outscored Wisconsin 27-0 in the second half. After being outgained 294-232 in the first 30 minutes, the Buckeyes outgained the Badgers 260-138 in the final two quarters, with 120 of those Wisconsin yards coming on their final two possessions with the outcome all but decided.

“We played Buckeye defense in the second half,” Young said. “Obviously, in the first half we had a lot of missed tackles.”

The Buckeyes won their third straight Big Ten championship, becoming the first conference team ever to win three outright titles in a row.

Wisconsin (10-3) was a 15-point underdog, but the Badgers played like a team that learned plenty from the loss in October. Taylor, limited to 52 yards in October, had 135 in the first half, including a 44-yard touchdown run on the game’s first possession.

After two Ohio State drives were stopped inside the Wisconsin 40, the Badgers went 80 yards in 14 plays for their second touchdown, the final 14 coming when Coan drew several Buckeyes away on a fake to Taylor and ran through a big hole up the middle.

Ohio State finally cashed in late in the second quarter by going 71 yards, with a 27-yard pass from Justin Fields to K.J. Hill setting up a 2-yard J.K. Dobbins score.

With 42 seconds left and Wisconsin having only one timeout, the Buckeyes figured to go into halftime trailing by only a touchdown. But Taylor broke a 45-yard run off left tackle to the Ohio State 30. Quintez Cephus then caught a pass despite being interfered with by Cam Brown — Okudah’s replacement — to the 1. Coan scored with 10 seconds left for a 21-7 halftime lead.

“I was a little nervous,” Day acknowledged. “We had a group of guys in that locker room that were barking at each other that they weren’t going to leave this place (as losers). Then we all got together and said, ’This is like life — it isn’t always going to work out the way you want it.’ The challenge was, we were going to find out what was really inside of us.”

The Buckeyes jumped on the Badgers from the start of the third quarter. A 50-yard completion from Fields to Chris Olave set up a one-handed, 16-yard touchdown catch by tight end Jeremy Ruckert to pull the Buckeyes within 21-14.

Ohio State’s defense, bolstered by the return of Okudah after he was medically cleared, followed with a three-and-out, and Wisconsin punter Anthony Lotti dropped the ball as he attempted to kick it. The Buckeyes took over at the 16 but had to settle for a field goal.

After Wisconsin missed a 49-yard field goal, the Buckeyes drove 69 yards for the go-ahead score. Hill had a 10-yard catch on third down to break David Boston’s Ohio State career record of 191 receptions to start the drive. He ended it with a 16-yard touchdown catch to give Ohio State its first lead, 24-21, with 2:23 left in the third quarter.

The swarming Buckeyes defense shut down the Badgers again, Ohio State followed with another touchdown drive, with Fields connecting on a 13-yard strike to Hill for the score to make it 31-21.

Fields finished 19-of-31 passing for 299 yards and was named the game’s most valuable player.

“This victory is a once-in-a-lifetime victory,” he said. “I struggled a little bit in the first half, but I just knew that I was a better player than I was actually playing.”

Dobbins had 168 yards on 31 carries. Taylor gained only 13 yards in the second half to finish with 148.

Now comes the waiting game as the Buckeyes await their College Football Playoff slot.

“I think we’re No. 1, point-blank,” Young said. “To see us come back — not just come back but dominate — I feel a team that can flip the switch like that is a No. 1-worthy team.”