Dwight Powell tacked on 16 points and Anthony Brown and Josh Huestis added 12 apiece for sixth-seed Stanford (20-11), which challenges third-seed Arizona State in the quarterfinals. Stefan Nastic also got in on the action with 10 points on 5-of-5 shooting.
DaVonte Lacy netted a game-high 25 points for Washington State (10-21). D.J. Shelton chimed in with 15 points and 11 rebounds and Dexter Drew-Kernich chipped in 11 points.
Stanford shot 55 percent from the floor, limited Washington State to 39.1 percent and connected on 11-of-12 from the free-throw line in the first half. The Cardinal led 35-28 at the break.
The Cougars did not go quietly in the second half, claiming a 50-47 lead with just under 10 minutes to play. However, the Cardinal ripped off a 10-0 run from there and never looked back.
Stanford outscored Washington State 36-26 in the paint.