Klay Thompson scored Washington State's first nine points and 18 of his 35 in the first half, and the Cougars nearly blew all of an early 20-point lead before pulling away from Portland 84-68 on Tuesday night.
Playing their annual game at Seattle's KeyArena, the Cougars (3-0) jumped to a 24-4 lead, then had to fend off a furious rally from the Pilots in the second half. Portland cut the deficit in half before halftime and pulled within 57-56 with 11 minutes left before the Cougars put it out of reach.
Washington State scored 23 of the next 27 points to build its lead back to 80-60. Faisal Aden added 21 points for the Cougars.
Jared Stohl led Portland (4-2) with 21 points and Nemanja Mitrovic added 17 for the Pilots.