Matthew Tucker ran for a pair of touchdowns to lead TCU past No. 18 Texas, 20-13, and give the Horned Frogs their 600th victory in school history.
Tucker finished with 57 yards on 14 carries for TCU (7-4, 4-4 Big 12), which has won two of its last three.
Trevone Boykin completed 7-of-9 passes for 82 yards with an interception while adding a game-high 77 yards on 10 carries in the win.
"We are growing up as a football team. It wasn't perfect, but we found a way to win," TCU coach Gary Patterson said. "We are still making mistakes at the quarterback position. We just need to keep growing up."
David Ash started the game at quarterback for Texas and completed 10-of-21 for 104 yards and two interceptions and a lost fumble before getting replaced in the fourth quarter by Case McCoy.
McCoy went 11-for-17 through the air for 110 yards, but tossed the game- sealing interception as the Longhorns (8-3, 5-3) had their four-game win streak snapped.
"I'm disappointed in the loss. We missed a great opportunity tonight to get back in the mix for some things," Texas coach Mack Brown said. "You can't win a football game when you have four turnovers and only gain one."
Texas received the ball first and drove as far as the TCU 30 with the aid of an unnecessary roughness penalty at the end of an Ash scramble, but Jason Verrett stepped in front of an Ash pass over the middle, giving the Horned Frogs the ball at their own six.
Boykin found Corey Fuller for a 35-yard gain on the next play and after converting a 4th-and-3 at the Texas 41 with a 4-yard reception by Fuller, Tucker capped the 14-play march with a 2-yard touchdown run with 5:29 left in the first quarter.
Tucker was initially ruled down at the 1-yard line on the play, but a review showed he was able to stretch the ball across the goal line as he was on top of a pile after leaping up the middle.
Marquise Goodwin's 41-yard return on the ensuing kickoff set the Longhorns up on their own 43, and Texas was able to capitalize on the favorable field position with a 25-yard field goal by Nick Jordan.
B.J. Catalon reeled off a 41-yard run on TCU's next touch to move the ball deep into Texas territory, but the Horned Frogs could not push the ball into the end zone and Jaden Oberkrom's 33-yard field-goal attempt missed wide right to keep it a 7-3 game just over four minutes into the second quarter.
Ash then hit Jaxon Shipley for gains of 14, 10 and 10 yards as Texas drove inside the Horned Frogs' red zone before Elisha Olabode intercepted Ash near the goal line and returned it to the TCU 19.
The Horned Frogs were held to a three-and-out, but Ash had the ball slip out of his hands as he was cocking back for a pass two plays later and TCU recovered the fumble at the Texas 16-yard line.
Three plays later, Tucker rumbled across the goal line from a yard out to give TCU a 14-3 lead at the break.
Adrian Phillips intercepted an errant Boykin pass on the opening possession of the third quarter and Texas was able to use the turnover to cut into its deficit.
After converting a 4th-and-1 at the TCU 41 with a 1-yard run by Joe Bergeron, Jordan connected on a 25-yard kick to bring the Longhorns within 14-6.
TCU countered with Oberkrom's 18-yard kick, and following a Texas punt, he connected on a 41-yard field goal to give the Frogs a 20-6 advantage less than two minutes into the fourth quarter.
McCoy, who also replaced Ash for the Longhorns' final drive of the first half, took over under center for Texas following another three-and-out by the Longhorns and was able to move the ball as far as the TCU 36, but his pass attempt on a 4th-and-3 fell incomplete to turn the ball over on downs.
McCoy later found four different receivers for double-digit gains on a 9-play, 82-yard march, which Jeremy Hills capped with an 8-yard touchdown run to bring Texas within 20-13 with 3:07 remaining in the game.
The Longhorns regained the ball at their own 34 with 1:44 left for a chance at the tying score, but after scrambling for 13 yards on the first play, McCoy was picked off by Sam Carter to seal the victory for TCU.
Texas leads the all-time series between the teams, 61-21-1 ... TCU improved to 4-1 on the road in conference play this season ... The Horned Frogs are now 14-9 against ranked opponents under Patterson ... Texas held a 300-299 edge in total yards ... Shipley paced all receivers with 80 yards on six receptions.