STILLWATER, Oklahoma (Ticker) -- Tony Allen scored 19 points for Oklahoma State, but it was his defensive play in the final minute that sealed the school's first regular-season conference championship in more than a decade.
Allen sprinted from behind to block Brandon Mouton's layup with 40 seconds remaining as the seventh-ranked Cowboys clinched the top seed in next week's Big 12 Conference tournament with a 76-67 victory over No. 10 Texas.
"I think this is special because when you walk away from the game you get to come back and see your face on that picture with the conference title," Allen said. "But we have one more game and we need to keep our heads up."
Oklahoma State (23-3, 13-2 Big 12) secured its first regular-season title since 1991. A win over Texas A&M on Saturday would give the Cowboys their first outright crown since 1965, when they were coached by Hank Iba.
When the buzzer sounded, hundreds of fans stormed the court at Gallagher-Iba Arena.
"I am really happy for this school because it has been almost 50 years since this school has won an outright championship in basketball," Oklahoma State coach Eddie Sutton said.
After a layup by Joey Graham, who paced the Cowboys with 20 points, gave Oklahoma State a 71-67 lead, Mouton appeared to have an easy layup. But Allen caught up to the play and knocked the ball out of bounds.
"I thought Tony did an unbelievable job on Mouton," Sutton added. "I thought that was really big, the way Mouton has been playing."
Mouton, who has held to just six points, got another chance but missed a 3-pointer with 36 seconds left. After the Cowboys made three free throws, Graham put the finishing touches on the win with a slam dunk with seven seconds remaining.
Oklahoma State, which has won 13 of its last 14 games, took control early in the second half, using a 15-3 spurt to open a 50-38 lead on Allen's three-point play with 14:14 remaining.
The Longhorns (22-4, 12-3) rallied behind Jason Klotz, who scored a career-high 19 points off the bench.
"It's pretty disappointing," Texas forward P.J. Tucker said. "We're sending our seniors off without a conference championship."
Texas closed to 62-61 on Tucker's jumper with 4:19 left. Ivan McFarlin's foul shot and Graham's jumper made it 65-61 with 2:55 to play.
Tucker contributed 14 points for the Longhorns, who had a four-game winning streak snapped.