Derrick Williams shrugged off pain in his right pinky to score 21 points and grab eight rebounds, and No. 21 Arizona beat Stanford 78-69 on Thursday night for its fourth straight victory.

The sophomore star had part of his shooting hand buried in tape and gauze to protect his pinky after it was bent backward against UCLA last week and still put together a complete performance. Lamont Jones added 15 points, and Jesse Perry scored 12 to help the Wildcats (19-4, 8-3) overtake Washington for the Pac-10 lead after the Huskies lost to Oregon State earlier in the night.

Jeremy Green had 21 points, and Josh Owens finished with 13 points and nine rebounds for a Stanford (11-10, 4-6) team that suddenly is struggling at home. After winning their first eight at Maples Pavilion this season, the Cardinal are 1-3 since.

The competition, of course, has improved dramatically.

Williams anchored a Wildcats front line that had more size and strength than Stanford could match. He did so despite the wrap that covered his pinky, stretched around his wrist and went up his right arm.

Not that the bandages seem to stop him.

Knowing contact would cause pain, Williams contested a dunk by Owens with more than 3 minutes remaining, forcing a key miss with a foul. Williams held his hand, grimacing, but perhaps the discomfort was worth it — Owens missed one of two free throws when both would've tied the game.

The Wildcats slowly built a lead from there, going ahead 68-62 on Williams' layup that capped a night filled with highlights. On one play in the first half, Williams dribbled baseline with his right hand, came back underneath the basket and finished with a left-handed layup — and drew the foul on Josh Huestis. Williams missed the free throw, but the basket gave Arizona a 26-17 lead.

The play had Stanford coach Johnny Dawkins stomping his foot, screaming for a timeout. The Cardinal showed some fight by scoring eight straight points in a run punctuated by one of John Gage's three 3-pointers in the opening half.

The Wildcats built back their lead before the break and seemed to be ready to pull away early. Then Stanford started the second half on a 12-1 run to go ahead 45-40, Arizona tied the game and things stayed close until the finish.