Ohio State built up an early lead and used solid defense to cruise past USC 24-7 at the Cotton Bowl in Arlington.
Buckeyes cornerback Damon Webb recovered a fumble that led to a touchdown and added a pick-six in the victory.
Ohio State forced four turnovers and J.T. Barrett rushed for two scores.
The Buckeyes end the season at 12-and-2. Trojan quarterback Sam Darnold accounted for three of the turnovers.
Ronald Jones the Second scored USC's only touchdown as it fell to 11-and-3 to end the season.