Even through a stalemate of the first half, Ohio State trying to hold Baker Mayfield and Oklahoma’s offense in check felt like a dam trying not to break.

In the second half, it did.

Mayfield looked every bit a Heisman Trophy contender in leading the No. 5 Sooners to a 31-16 victory Saturday night in front of 109,088 at Ohio Stadium. It was the most lopsided home loss since the Buckeyes lost 46-20 to Illinois on Nov. 25, 1999.

Using his feet to escape pressure and a strong arm to rifle balls to receivers, Mayfield completed 27 of 35 passes for 386 yards and three touchdowns. It was sweet redemption for Mayfield, who played a subpar game in Ohio State’s 45-24 victory in Norman last year.

The soon-to-be-former-No. 2 Buckeyes (1-1) now have almost no margin for error if they want to reach the College Football Playoff. If they don’t fix their labored offense, it’s a moot point.

J.T. Barrett hit 19 of 35 passes for just 183 yards. The deep game was again nonexistent and receivers seldom caught shorter passes in stride, which was key in last week’s victory over Indiana.

The Buckeyes running game couldn’t do enough to overcome it. Freshman J.K. Dobbins, who ran for 181 yards in his debut, gained only 72 yards in 13 carries. Mike Weber returned from his hamstring injury but got only three carries for 29 yards.

Ohio State’s only touchdown came on its first possession of the second half, and that was set up by Parris Campbell’s 56-yard kickoff return. The Buckeyes went 44 yards in seven plays to score, with Dobbins scoring his first career touchdown on a 6-yard carry.

That gave the Buckeyes a 10-3 lead. It wouldn’t last long.

Oklahoma (2-0) had driven into Ohio State territory in all five of its possessions in the first half. The Sooners came up empty on the first four, thanks to a fourth-down incompletion, two fumble recoveries and a missed 37-yard field goal.

Oklahoma finally scored with 25 seconds left in the half on a 35-yard field goal to tie the score at 3.

The Sooners would not be denied in the second half.

But Oklahoma answered quickly. Mayfield hit freshman tight end Grant Calcaterra, who had a key drop in the first half, for a 21-yard catch. Mayfield then threw a play-action pass to fullback Dimitri Flowers, who outran safety Erick Smith to the end zone for a 36-yard score to make it 10-10.

The Buckeyes countered with their longest drive of the game. Three Dobbins runs for 40 yards set up a 31-yard pass from Barrett to Austin Mack ruled to be inbounds after a video review.

But the drive stopped there. Barrett was stuffed on two run plays and his pass to an open K.J. Hill went off his fingertips before Scott Nuernberger kicked a field goal.

After that, Oklahoma took control. The Sooners needed only four plays to go 92 yards to take their first lead late in the third quarter. Mayfield hit a beautiful 42-yard pass to Mykel Jones just over cornerback Kendall Sheffield. He then threw to Lee Morris for an 18-yard score and a 17-13 lead.

The Sooners stretched the lead with a touchdown on their next drive, going 64 yards in seven plays. The final 10 came when Mayfield looked like he was going to scramble and then flipped the ball to Trey Sermon.

Any real suspense ended when Barrett was intercepted on the ensuing possession and Oklahoma added another touchdown for a 31-13 lead.

Nuernberger added a third field goal, but the Buckeyes’ onside kick failed, and the Horseshoe began to empty. By the end of the game, Sooner fans chanted "OU! OU!"

It was a dispiriting performance for a team with such high expectations. The Buckeyes overcame a similar loss in 2014 in their home opener to Virginia Tech to win the first College Football Playoff. But they’ll have to show a lot of improvement if that’s to even be a possibility.

The visiting team has now won all four games in the all-time Ohio State-Oklahoma series.