At critical junctures Saturday, Ohio State’s offense leaned on Justin Fields.

On the first third down of its opening touchdown drive, he gained 14 yards on a quarterback draw. On fourth-and-5 late in the second quarter, Fields sprang forward for 22 yards, picking up a first down inside the 5-yard line.

Fields rushed a career-high 21 times in a 28-17 win over Penn State at Ohio Stadium, picking up 68 yards.

In no game had Fields logged more than 13 carries, but this week in anticipation of a tougher matchup, coach Ryan Day told Fields that he was likely due for an increased workload on the ground.

“He’s up for the challenge,” Day said. “Some quarterbacks, they look at you sideways when you have that conversation. He doesn't. He looked back, ‘Whatever it takes, Coach.’ You talk about a tough kid, he is tough.”

Several times after the game, Day gushed about Fields’ toughness as he gritted through Penn State’s defense on a damp afternoon. His nonthrowing hand was caught bleeding in the first half, and he also received medical attention on the field late in the fourth quarter after he had been tackled. The Buckeyes were then trying to milk the clock.

“He's a warrior,” Day said. “I'm telling you, he's tough.”

The emphasis on running Fields came despite possible matchup concerns.

Penn State was ranked fourth in the nation in rush defense and had allowed only 2.19 yards per carry, the fewest by any team. Fields still ran for an average of 3.2 yards per carry, or 4.9 yards per carry excluding yards lost to sacks.

If the Nittany Lions wore down Fields, he had a similar effect on them.

“That kid is an athlete,” Penn State safety LaMont Wade said. “It’s like tackling a freakin’ running back instead of a quarterback. He’s a tremendous talent. He’s a hard guy to stop.”

Not all of Fields’ rush attempts were by design. On some occasions, he scrambled without a receiver open, or he kept the ball on a read-option play.

The carries were a significant boost, Day thought, because they made Penn State’s tough rush defense track an additional runner.

"When you're playing against really good defenses, that's something you have to do," Day said, "and I thought he made great decisions."