Washington (20-8, 13-3) erased a 45-32 deficit with 11 minutes left in the game to win.
Ultimately, the game came down to free throws. WSU (14-14, 6-10) went 11 of 12 to keep the game tied at 28-all despite shooting 27 percent in the first half.
In the second half, the Cougars shot 6 of 20 from the free throw line, while the Huskies, who only went 2 of 5 in the first half, finished 17 of 24.
The Cougars out-rebounded the Huskies 42-35.
CJ Wilcox finished with 16 points for Washington while Abdul Gaddy finished with 10.
Brock Motum led the Cougars with 17 points and Marcus Capers added 14.