Police spokeswoman Sherry Mercurio didn't know how many people were injured. She said the arrests were for carrying open containers of alcohol, rioting, resisting arrest or setting the fires.

Celebrations began Saturday afternoon, after Ohio State edged Michigan 14-9 to complete a 13-0 regular season. The Buckeyes next will play in the BCS national championship game at the Tostitos Fiesta Bowl on Jan. 3.

Police at Ohio Stadium used pepper spray to subdue fans who swarmed the field and pushed toward a goal post.

A little after midnight, police used tear gas and pellets to disperse a crowd of several hundred east of Ohio State's campus.

At one point, nine cars were piled together and burning, Mercurio said. Disturbances continued in portions of a 10-block area for several hours.

"Once we'd get one street under control, the crowds would move to one or two others and things would break out again,'' she said.

Streets were mostly empty near campus Sunday morning, with a few traffic barricades at some intersections and some uprooted park benches.

There were 21 arrests, but none was related to the on-field celebration. Pepper spray was used on fans to keep the goal posts standing as police remembered a similar episode two years ago, when car windows were broken by a group of people who paraded the goal posts down a street.

"I feared for my life,'' Washington athletic director Barbara Hedges said following the dramatic Apple Cup, which was decided by a referee's call that went against the Cougars.

None of the players on either side was hurt, but some journalists had cuts and needed minor treatment.