KANSAS CITY, Mo. (AP) -- The first two times that Baylor played Oklahoma this season, the Bears struggled through the opening minutes and failed to get on track until it was a bit too late.
This time, they delivered the opening blow.
The Bears roared to a 21-point lead early in the second half Thursday night, and then held off a frantic rally by the Sooners for a 78-73 victory in the Big 12 tournament quarterfinals.
Isaiah Austin finished with 18 points for the seventh-seeded Bears (23-10), who became the first lower-seeded team to win in this year's tournament. Baylor will face the winner of Texas-West Virginia in the semifinals on Friday night.
"They beat us the first two games, and coach always says it's hard to beat a team three times," said Cory Jefferson, who added 14 points and 11 boards for Baylor. "I'm sure they knew that. They were prepared and we were going to make sure we were prepared."
Cameron Clark scored 19 points and Buddy Hield had 15 for the second-seeded Sooners (23-9), who spent most of the second half frantically rallying from a 52-31 deficit.
They got within 72-68 on Hield's 3-pointer with 1:27 left, and had a chance to get even closer when Royce O'Neale turned it over for Baylor. But a 3-pointer by Jordan Woodard with about a minute left was off the mark, and O'Neal came through with a pair of free throws.
Oklahoma had a couple of open layups on the ensuing possession, but opted to toss it out to Clark for a 3-pointer. He missed it, the Sooners had to foul again and Brady Heslip -- one of the best free-throw shooters in the Big 12 -- knocked down two more to help the seal the win.
"Baylor from the start was more aggressive, and dictated, and I thought we were reacting most of the first half," Oklahoma coach Lon Kruger said. "They played with more urgency."
O'Neal wound up with 12 points and 10 rebounds for the Bears. Kenny Chery added 12 points and seven assists, and Heslip also finished with 12 points.
"That's when we're at our best," Chery said, "when we're sharing the ball."
It was the ninth win in 10 games for Baylor, which has gone from NCAA tournament bubble to knocking on the door of the Big 12 title. The Bears are in the semifinals for the fifth time after ending a four-game skid against the Sooners that included a pair of losses this season.
It also gave Baylor coach Scott Drew his 201st win, moving him into a tie with Bill Henderson for the most in school history, though he preferred to deflect the attention to his players.
"Any coaching honor is a direct reflection of the players," Drew said. "None of us coaches have made any buckets. It's all the players' work."
The Sooners came into the game tied for the Big 12 scoring lead at better than 82 points per game, but they shot 38 percent in the first half and were thoroughly dominated on the glass.
Baylor took advantage of the cold start to score the game's first 10 points. It maintained that comfortable advantage until the closing minutes of the first half, then used a 10-2 run that helped the Bears carry a 47-31 lead into the locker room.
"They hit us first," the Sooners' Ryan Spangler said. "They got on a roll and it was hard to stop."
The lead grew to 21 points in the opening minutes of the second half, the Bears capping a surge with an alley-oop dunk by Austin that brought their smattering of fans to their feet.
Oklahoma finally started to show a pulse, though.
Isaiah Cousins hit a 3-pointer and Clark scored three straight baskets, the last on a stylish dunk in transition. By the time Tyler Neal scored on a nifty scoop shot in the paint, the Sooners had embarked on a 13-2 run.
The Bears answered with a flurry of their own, but a basket by Cousins with about three minutes left and a 3-pointer by Hield -- who had been 1 for 7 from the arc at that point -- got the Sooners within 69-64 and started to give them reason to believe.
It turned out to be false hope. Baylor promptly shut the door on their inspired comeback.
"The second half, most teams are going to compete like crazy when you dig yourselves a hole," Kruger said, "and our guys did that."
