Rawle Alkins contributed 16 points and eight rebounds for Arizona (22-6, 12-3 Pac-12), and he sank two 3-pointers in overtime at Gill Coliseum.
Dusan Ristic had 14 points and Alkins added eight rebounds for the Wildcats, who announced three hours before the game that Trier had been suspended by the NCAA after testing positive for a banned substance.
Alkins tied the game at 61 with two free throws around an Oregon State timeout with 14.2 seconds remaining in regulation.
His first three-pointer gave the Wildcats a 68-64 lead with 2:59 left in overtime, and his second capped a 10-0 run for a 73-64 edge with 1:11 left.
Ethan Thompson tied a season high with 20 points and grabbed eight rebounds, and Tres Tinkle had 14 points for the Beavers (13-14, 5-10). Oregon State lost for the seventh time in nine games.
Ayton, who has 18 double-doubles this season, helped first-place Arizona maintain a 1-1/2 game lead over USC (20-9, 11-5) in the Pac-12.
Drew Eubanks had 13 points and Stephen Thompson Jr. added 12 for the Beavers, who were attempting to beat a ranked Arizona team at home for the second time in four seasons.
Tinkle, who also had six rebounds and six assists, has scored in double figures in 30 consecutive games. He is only Pac-12 player to score in double figures every game this season.
Ethan Thompson's 3-pointer for a 64-63 lead at a minute into of overtime was the Beavers' first field goal since brother Stephen's jumper with 9:08 remaining in regulation. Oregon State made nine free throws down the stretch.
Ristic, a senior, has scored in double figures in 11 straight games, extending the longest such streak of his career. With the victory, he tied Kaleb Tarczewski and Matt Muehlebach with 110 wins at Arizona, the school record.
Trier missed the first 19 games of the 2016-17 season while serving an NCAA suspension after testing positive in September 2016 for a banned substance, later identified as Ostarine.
Trier entered the weekend second in the Pac-12 with a 19.6 scoring average and fourth with a 43.0 shooting percentage from 3-point range. He is averaging 3.2 rebounds and 3.2 assists per game and he has made 85.4 percent of his free-throw attempts.
--Field Level Media
Arizona | Oregon St. | |
DeAndre Ayton 19 | Scoring | Ethan Thompson 20 |
DeAndre Ayton 4 | Assists | Tres Tinkle 6 |
DeAndre Ayton 12 | Rebounds | Ethan Thompson 8 |
Rawle Alkins 6 | Free Throws Made | Tres Tinkle 7 |
Emmanuel Akot 1 | Steals | Tres Tinkle 2 |
DeAndre Ayton 3 | Blocks | Alfred Hollins 1 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
Arizona | 75 | 48.2 | 5-16 | 16-24 | 11 | 34 | 4 | 4 | 13 |
Oregon St. | 65 | 40.0 | 7-22 | 14-17 | 15 | 26 | 2 | 6 | 16 |