Derrick Williams had 26 points and eight rebounds to lead No. 13 Arizona to its seventh straight Pac-10 victory, 79-70 over visiting Washington State on Thursday.

Williams was again dominating in the post for Arizona (22-4, 11-2 Pac-10), which also got 12 points from Solomon Hill and 10 from Lamont Jones. Williams finished 7 for 10 from the field and 12 for 12 from the free throw line.

Klay Thompson scored a game-high 30 points, and DeAngelo Casto had 14 points and five rebounds for Washington State (17-9, 7-7 Pac-10).

Arizona led by as many as 17 points early in the second half before Washington State got as close as 64-59 on a Thompson layup with 6:35 left.

Arizona hosts Washington (10-4 Pac-10) on Saturday.