CORVALLIS, Ore. (AP) — Headed to the line with Arizona down two points late in the game, Rawle Alkins thought about his mechanics, as he'd uncharacteristically missed half his free throws on the night.

"Those were probably the biggest free throws of my life," Alkins said. "I hit the first one, and I knew the next one was going in."

His confidence carried into overtime.

Deandre Ayton had 19 points, 12 rebounds and three blocks, and No. 14 Arizona, minus one of its star players, beat Oregon State 75-65 on Thursday.

Alkins added clutch scoring with 16 points and eight rebounds, and Dusan Ristic had 14 points for the Wildcats (22-6, 12-3 Pac-12), who were without guard Allonzo Trier.

"It was a tough-fought win, an ugly win, but I'm just glad we got it done," Alkins said.

Trier was declared ineligible by the NCAA after a trace amount of a banned substance was found during a late January drug screening, according to a university statement released Thursday.

Alkins' free throws with 14 seconds left tied it, and he made two 3-pointers as part of a 10-0 surge that put the Wildcats up 73-64 with 1:11 left in the extra period.

"Rawle made some really big plays," said Arizona coach Sean Miller.

Ethan Thompson had 20 points and eight rebounds for the Beavers (13-14, 5-10). Tres Tinkle added 14 points, six rebounds and six assists.

Oregon State didn't attempt a free throw in the first half, but shot 14 for 17 from the line for the rest of the game.

Arizona went on an 11-0 run, fueled by six points from Ristic, to go ahead 27-15 with 7:15 left in the first half. Oregon State went more than six minutes without scoring.

The Wildcats went to the break up 37-29.

The Beavers responded after halftime and Gligorije Rakocevic's jump hook tied the game at 50-all with 9:51 remaining.

There were several lead changes from there before Stephen Thompson Jr. missed a jumper before the regulation buzzer for Oregon State.

"We had plenty of chances, multiple chances, to knock down (a shot) with under a minute to go in regulation and just couldn't pull it out," Oregon State coach Wayne Tinkle said.

Arizona is appealing the suspension for Trier, who was averaging 19.6 points, 3.2 rebounds and 3.2 assists.

"The amount detected was minuscule by scientific standards and appear to be a remnant of a substance, which the NCAA agreed, that Allonzo unknowingly ingested in 2016," the university statement reads.

BIG PICTURE

Arizona: Coming into Thursday, the Wildcats had won 11 of their last 12 games against Oregon State, with an average margin of victory of 16.5 points. ... Ristic, a senior, reached 110 career victories and tied Kaleb Tarczewski and Matt Muehlebach as the winningest players in program history.

Oregon State: Tinkle is the only Pac-12 player to score in double figures in every game this season. ... The Beavers are 12-4 at home this season but 0-8 on the road.

MISSING PLAYERS

Trier wasn't the only Arizona player who missed Thursday's game. Freshman forward Ira Lee didn't travel with the team due to a concussion suffered in practice earlier this week. Ayton said that with two players out, other teammates needed to increase their contributions. "We really needed our guys off the bench and they stepped up to the plate," he added.

ROAD SWEEP?

Arizona is looking for the road sweep as it travels to Oregon looking for payback after an 85-58 loss last season in Eugene. "We didn't forget about that," Alkins said. "As long as we bring our A-game and we play hard, we can beat anybody in the country."

HOLLINS

Alfred Hollins, who had averaged 16.3 points in four starts for Oregon State, sprained his ankle in practice on Tuesday and was taken out of the opening lineup due to the injury, Wayne Tinkle said. Hollins was scoreless in five minutes on Thursday. "We went to him early and he wasn't himself," Tinkle said.

UP NEXT

Arizona plays at Oregon on Saturday.

Oregon State hosts Arizona State on Saturday.