Jordan Bachynski added 12 points for the Sun Devils (20-7, 9-5 Pac-12).
Arizona State finished the first half with a 14-3 run to lead 36-22 at the break and was up by as many as 21 before Washington State cut it to eight in the late going.
The Sun Devils, one of the worst free-throw shooting teams in the country this season, sealed the win with eight straight in the final 1:35.
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Andrew White III will return to the Nebraska men's basketball team next season after removing his name from the NBA draft.
Mike Brey is looking at former Notre Dame players to fill two assistant jobs that have opened up with the departures of Martin Ingelsby and Anthony Solomon.
Purdue's 2016-17 prospects got a jolt Wednesday when forward Caleb Swanigan announced he will return for his sophomore season.