KANSAS CITY, Mo. (AP) It took Oklahoma about 20 minutes to find its stride Thursday night.
Once the Sooners did, they never lost it.
Buddy Hield scored 22 points, TaShawn Thomas added 17 points and 10 rebounds, and the No. 15 Sooners took advantage of an early second-half run to beat Oklahoma State 64-49 in the quarterfinals of the Big 12 tournament.
Jordan Woodard added 11 points and Isaiah Cousins had 10 for the third-seeded Sooners (22-9), who beat the No. 6 seed Cowboys (18-13) for the seventh time in their last eight meetings.
''Two different halves,'' Oklahoma coach Lon Kruger said. ''The second half was much more in rhythm.''
Oklahoma advanced to play No. 13 Iowa State in the semifinals Friday night. The second-seeded Cyclones needed a buzzer-beater to beat Texas 69-67 in an earlier quarterfinal.
Le'Bryan Nash had 27 points and 12 rebounds for Oklahoma State, which may have needed a win in the Big 12 tournament to feel good about its chances on Selection Sunday.
''Our numbers speak for themselves, no question,'' Cowboys coach Travis Ford said. ''We put that work in. The numbers speak for themselves.''
The game between longtime rivals went off without any disturbances just days after a video showing members of an Oklahoma fraternity engaging in a racist chant first surfaced.
The video touched off a series of protests on campus last weekend, some of them involving members of the basketball team. Sooners coach Lon Kruger denounced the video and joined football coach Bob Stoops in demonstrations against the fraternity members' actions.
By the time the Sooners reached the Sprint Center, though, they were all business.
Good thing, too, because Oklahoma State didn't let them have anything easy early on.
Despite foul trouble that forced Cowboys coach Travis Ford to go 12 players deep in the first half, they still managed to muddy up the game enough to hang around. The Sooners shot just 7 of 30 from the floor over the first 20 minutes, the game having all the flow of quicksand.
''Our offense was too stagnant in the first half,'' Hield said.
Oklahoma State led 32-23 early in the second when the Sooners went on a run.
Hield kicked it off with seven straight points for Oklahoma, and then capped it with a long 3-pointer that gave the sooners a 39-35 lead with 13 minutes left in the game.
Nash tried his best to keep the Cowboys in the game, scoring on an array of spin moves at the rim, a couple of soft floaters and at the foul line. Over more than 10 minutes midway through the second half, the senior forward was the only player wearing orange to score.
''They were smart enough to figure out, `Hey, we need to give him the basketball,''' Ford said ''and he made some strong moves.''
He couldn't do it alone, though, and the Sooners' balance eventually paid off.
Thomas started to assert himself in the post, Hield kept finding good looks, and Woodard shook off an 0-for-5 first half from the floor to add a couple of key free throws, helping the Sooners end a three-game losing streak in the Big 12 tournament.
''Our last game with them, they really took it from us in the second half. This game, we had open shots - wide open shots,'' Ford said. ''We just didn't convert.
He may have scored 22 points, but Hield was just 5 for 15 from the floor, prompting him to make a vow after the game: ''I'm going to shoot better tomorrow, I promise you that.''
Like Ford, Nash said he wasn't worried about the Cowboys' chances of making the NCAA tournament. ''I'm always confident in my team and what we did and our resume,'' he said. ''We had some good wins, three top-10 wins. I feel like everybody sees us as a tournament team.''
Oklahoma State: Nash finished two points shy of his career high. ... The Cowboys have lost six of their last seven, their lone win coming against TCU.
Oklahoma: Hield finished 9 for 9 from the foul line. ... The Sooners did not get any points from their bench. ... Oklahoma committed just six turnovers.
Oklahoma State heads back to Stillwater to await its postseason fate.
Oklahoma faces Iowa State, one of two teams to beat the Sooners in their last 12 games.