Moreland had 11 points and 14 rebounds and Challe Barton added 11 points for Oregon State (13-12, 3-9 Pac-12) which had lost four of its previous five games.
Washington State (11-14, 2-10) was paced by DaVonte Lacy who scored a game-high 27 points while Brock Motum registered 16 points and Royce Woolridge chipped in 10 points. The Cougars have lost five straight and six of their last seven.
In the first half Oregon State shot 40 percent from the floor and was a perfect 8-of-8 from the free-throw line to take a 33-26 lead at the break.
The Cougars trailed by as many as 15 points in the second half but rallied behind a 58.3 percent shooting effort, including a 10-of-15 showing from 3-point range, in the final 20 minutes. An 18-4 run late in the game cut the Beavers' lead to just a single point, 64-63, with 1:14 remaining. However Nelson hit a layup and Langs Morris-Walker added a free-throw to make Lacy's 3-pointer at the buzzer irrelevant.
Oregon State outscored Washington State 30-16 in the paint while owning a 34-25 edge in rebounds.
02/14 00:36:23 ET