Angus Brandt scored 16 points to lead Oregon State to a 68-57 win over Washington State on Thursday.
Devon Collier added 14 points for the Beavers (14-11, 6-7 Pac-12), who improved to 11-2 in Gill Coliseum on the year. Oregon State has three of its five remaining games at home.
DaVonte Lacy scored 18 points for Washington State (9-17, 2-12 Pac-12) and D.J. Shelton had 10 points and 11 rebounds.
Lacy had nine of the Cougars first 12 points, but then went scoreless for nearly 20 minutes.
After the Beavers made the first basket of the game, Washington State went on an 8-0 run.
The Cougars promptly went cold, however, and Oregon State outscored Washington State 25-6 over the next 12 minutes. The Beavers took a 27-16 lead with 4:34 remaining.
Washington State didn't score for more than 4 minutes during that stretch. But Oregon State followed up with its own scoreless 4-minute span, and went to the break up 30-26.
After the opening minutes of the second half, the Cougars couldn't get closer than five points.
Oregon State beat Washington State 66-55 in the teams' first meeting this season on Jan. 22 in Pullman.
The Beavers six Pac-12 wins are more than or equal to its total conference wins in 15 of the last 20 seasons.
Oregon State came into the game led by Roberto Nelson with 21.3 points per game. He had 12 points on 1-9 shooting on Thursday, but added seven assists for the Beavers.
Eric Moreland, who had one block against Washington State, needs three more to become Oregon State's career leader in that category. Scott Haskin holds the record with 172 blocks.
Washington State has lost its last five games, and nine of its last 10. The team has not won a Pac-12 game away from Pullman, and is ranked last in the conference in points scored per game and free throw percentage.
The Cougars shot 16-28 from the line on Thursday. The Beavers went 25-36 from the charity stripe.
Lacy entered the game leading the Cougars with 19.4 points per contest, and he had scored more than 30 in two of the Cougars three previous games.
He missed eight games this season due to appendicitis and a rib injury. The Cougars won only two of those contests, and averaged nearly 17 fewer points without him.