Langston Morris-Walker made a layup that put Oregon State up 29-22 early in the second half. The Beavs pulled away from there with a 10-2 run capped by two Payton layups to lead 35-24 with 13:55 left in the game.
A big dunk by Payton with 4:38 left gave the Beavers a 51-40 lead.
Oregon State is now 16-7 overall -- its best record since the 1989-90 team started 19-4. That was also the last time Oregon State went to the NCAA tournament.
Malcolm Duvivier added 14 points for the Beavers, who also improved to 7-4 in Pac-12 conference play.
Washington didn't score for nearly the first six minutes of the game and didn't get a bucket until 10 minutes had gone by. But OSU had its own problems on offense and led just 21-18 at the half.
But the Beavers were exceptional on defense from start to finish - Oregon State forced 22 Washington turnovers.
The Beavers evened up the season series, the Huskies won the first game 56-43 in Seattle on Jan. 15.
But this one was all about home sweet home. And as the Beavers continue to win, they continue to get more attention. A season-high 9,114 fans attended the game Sunday at Gill Coliseum.
UP NEXT: Oregon State visits UCLA on Wednesday night.