Damion James added 13 points and 18 rebounds for the Longhorns, making four free throws in the final 36 seconds to help maintain the lead. After the game, Texas players hoisted the championship trophy at midcourt. Texas has won a share of the conference title two of the last three seasons and three overall in 10 years.
Byron Eaton and Terrel Harris each scored 12 points for the Cowboys (16-14, 7-9).
Augustin had 11 points as Texas took a 33-27 lead into halftime. The Cowboys used the beefy Eaton and several players to try to guard Augustin, holding him to 2-of-7 shooting in the half, but couldn't cut off his drives to the basket.
Oklahoma State opened the second half with a 10-4 run that tied it at 37 when Marcus Dove flushed a rebound off a miss. The play started when Augustin lost the ball on a drive to the basket and Eaton threw the ball out to start a fast break. The Cowboys briefly held the lead until Augustin, probing the perimeter for an opening to drive, casually pulled up for a long 3.
Augustin and the Cowboys traded shots for the next three minutes. On one play, Eaton casually tracked down an errant pass and Augustin snuck in behind him, poked it away and coasted in for an uncontested layup and a 46-43 Texas lead.
The Longhorns needed everything they could get from Augustin as Texas' big players all but disappeared for much of the game. Until Gary Johnson made two free throws with 7 minutes left, forwards Johnson and Connor Atchley had a total of three rebounds and eight points.
Eaton pulled OSU within 51-49 when he lowered his shoulder on a drive against Augustin, drew a foul and made two free throws with just over four minutes to play.
A.J. Abrams, who was 1-of-13 while misfiring from just about everywhere on the court, finally made two in a row, rattling in a critical 3-pointer for a 56-51 lead with 1:44 to play.
Texas could have settled it when Augustin dished to Atchley in the paint, but he missed the layup and a tip-in on the rebound before Harris swished a 3-pointer from the corner to get the Cowboys within two.
James then got to the free throw line. After the Cowboys missed another long shot, Augustin appeared trapped in the backcourt but avoided three defenders and fired a baseball pass to Abrams at midcourt to help bleed more time of the clock. James finished it with two more free throws with four seconds left.