Faisal Aden scored 20 points for the Cougars (19-10, 9-8 Pac-10).
In the final 4:45, Washington State had one shot from the floor: a layup by Aden, after he stole the ball from Vucevic. The basket put the Cougars up 77-70 with 1:41 remaining.
The rest was done at the line, where Washington State went 10 of 14 in the final 4:45, and 8 of 8 in the final 3:03.
The Cougars lost guard Reggie Moore to a sprained ankle seven minutes into the game. He will be re-evaluated on Friday.