J'Covan Brown chipped in 15 points, while Dexter Pittman and Gary Johnson each scored 14 for the Longhorns (23-7, 9-6 Big 12), who dropped out of the Top-25 following Saturday's 16-point loss at Texas A&M.
Texas has a chance to finish its up-and-down campaign on a high note with a win at No. 21 Baylor in its regular season finale on Saturday.
Tony Crocker and Cade Davis netted 24 and 22 points, respectively, for the Sooners (13-16, 4-11), who have dropped seven in a row since knocking off the Longhorns in Norman on February 6th. Tiny Gallon had 15 points and nine rebounds in defeat.
Brown, who had to be carted off the court on Saturday following a scary fall that left him with a neck strain, made a bucket to give Texas its first lead of the second half, 58-56, with nine minutes to play.
The field goal was part of a 16-4 run that Pittman capped three minutes later on a tip-in for a 68-60 lead.
It was at least a two-possession game the rest of the way, as Texas finished up its home slate with a solid 15-2 record.
Oklahoma led by as many as 13 in the first half, but Texas pulled within 40-38 by intermission.
Tommy Mason-Griffin's three-pointer capped the Sooners' 9-0 run to start the second half, but again the Longhorns had an answer, scoring 11 of the next 13 points for one-possession game.