Shelton entered Wednesday's contest shooting 17 percent from behind the arc but was 4 of 4 from distance against the Beavers (11-7, 3-3) and 10 of 15 overall from the field.
"I don't know if he'd made that many 3-pointers all year," Cougars head coach Ken Bone said of the redshirt senior. "It'd be great to see that every night."
Shelton said he has made an effort to be aggressive on the floor, and that as a senior, he needs to step up and "basically be a beast out there."
Despite shooting a season-high 59.1 percent from the field (13 of 22) in the first half, Washington State (8-11, 1-6) was plagued by turnovers, committing 13 on the night. The multitude of unforced turnovers allowed Oregon State to take take the lead early on and never relinquish it.
"We had six or seven turnovers after 8 or 10 minutes," Bone said. "We were careless with the ball, you can't do that. It's been hard enough for us to score as of late, without DaVonté (Lacy) in; it's been more of a struggle so we can't turn the ball over and give ourselves a great chance to win the game."
Oregon State had 11 turnovers in the game and scored eight points off WSU's offensive miscues.
Shelton said the turnovers were borne of attempts to force sets on the offensive end, and those missed opportunities threw them off once they were able to make a defensive stop.
The scoring woes continued for all except Shelton and redshirt freshman Que Johnson, who had 15 points and three assists. WSU shot 50 percent from the field (24 of 48) but the other starters combined for just six points on 2-of-10 shooting.
Bone said the lack of points from the rest of the team remains a concern.
"You can't just have two guys," he said.
With Lacy expected to be out of the lineup for a few more weeks, Johnson will likely continue to be called upon as the primary source of scoring, as he was Wednesday night until Shelton exploded in the second half. Since Lacy was injured against Arizona State, Johnson has averaged 16 points per game.
"I just focus on being more aggressive with DaVonté out," Johnson said. "Even when he gets back, Coach is still going to look for me offensively, so it's going to be a good one-two punch with me and DaVonté ."
The Cougars take the court again on Sunday (4 p.m. on Pac-12 Networks) to host the Oregon Ducks.
"They attacked more than we did and at the end we were fouling," said Bone, whose team made just one free throw. "They should've shot more than us. Why we shot four? I'm not sure yet."