Michael Flowers poured in 27 points, Mouhamed Gueye scored eight of his 19 in overtime and Washington State handed Oregon State its 15th straight loss 103-97.
Cougars' Gueye and Abogidi each scored career-highs while combining for 46 points as Washington State opened a home-and-home series with arch-rival Washington with a 78-70 win.
Boogie Ellis hit a 16-foot jumper from the foul line with 0.2 seconds left to give No. 17 Southern California a 62-60 comeback victory over Washington State on Sunday.
Johnny Juzang scored 19 points, Jaylen Clark had a career-high 18 points and 11 rebounds, and No. 13 UCLA rolled to a 76-56 victory over Washington State.
Endyia Rogers scored 17 points, Te-Hina Paopao added 14 and No. 24 Oregon rolled past Washington State 83-30 for the largest margin of victory in the 90-game series.