Cal (18-14) turned a close game into a rout with an impressive shooting display, hitting 14 of 15 shots spanning halftime to build a 17-point lead.
The eight-seeded Bears shot 58.5 percent overall and went 8 of 12 from 3-point range to earn a spot in Thursday’s quarterfinals against No. 5 and top-seeded Arizona.
Jordan Mathews had 19 points and Tyrone Wallace added 12 for California.
Washington State (13-18), the tournament’s No. 9 seed, struggled defensively and failed to hit a 3-point shot until late in the second half.
Ike Iroegbu led the Cougars with 17 points. Leading scorer DaVonte’ Lacy was held to 9 points on 4 of 11 shooting and struggled with emotions on the bench after his final game.