No. 12 seed Oregon State upset the fourth-seeded Oklahoma State Cowboys at Hinkle Fieldhouse, 80-70, on Sunday night to advance to the Sweet 16 in the Midwest region of the NCAA tournament.

Senior guard Ethan Thompson led the Beavers with 26 points on 5-of-11 shooting and seven rebounds. Oregon State also got a heavy lift from junior forward Maurice Calloo, who scored 15 points in the first half.

Oklahoma State star freshman Cade Cunningham, a first-team All-American and projected NBA lottery pick, finished with 24 points, four rebounds and three assists, but the Cowboys rushed shots down the stretch and at times failed to get him the ball.

The Beavers scored 44 points in the first half, the most allowed by Oklahoma State in a first half this season. Their 44-30 halftime lead was also Oklahoma State's largest halftime deficit of the season. The Cowboys shot 27.7% from the floor for the game, their worst shooting performance since 2014.

After the game, Thompson said, "This team had some big goals going into the season. One of them was winning a Pac-12 tournament championship, a Pac-12 regular-season championship as well, of course, but we didn't do that. We got the tournament championship. Ultimate goal is to win the NCAA championship."

Oregon State coach Wayne Tinkle was holding back emotions after the game. His father was a dean of students at Loyola-Chicago, the team the Beavers will face in the Sweet 16 on March 27.

"I grew up on their campus," Tinkle said.

He added, "Coach Moser has done a hell of a job. They're a great team. This is really going to mean something extra special for me and my family."

Oregon State was picked to finish last in the Pac-12 and had to win the conference tournament just to make the NCAA field. The Beavers pulled that off, then cruised past No. 5 seed Tennessee in the first round.

Tinkle took the opportunity during his media availability to speak on the Pac-12, now 6-0 in the NCAA tournament.

"We've got some talented, talented teams in our league," he said. "We're obviously putting everybody on notice. I'm very happy for our program, but I'm extremely happy for the Pac-12 conference.

"Maybe now we'll get some damn respect."

Oregon State has now won five straight games in elimination settings -- three in the Pac-12 tournament and two in the NCAA tournament. According to ESPN Stats & Information research, the Beavers' BPI chance to win was under 30% in each of those games, and the odds they would win all five was approximately 1 in 2,800.

With Oregon State's win, there will be at least four double-digit seeds in the Sweet 16 for the third time, according to ESPN Stats & Information. Oral Roberts (15), Oregon State (12) and Syracuse (11) are already in, and (11) UCLA plays against (14) Abilene Christian on Monday.