AUSTIN, Texas (AP) - There was no Thanksgiving magic for Case McCoy this time.
Instead of a late game-winning rally, there was just a game-killing interception.
Playing in relief of David Ash, McCoy sparked No. 18 Texas to a late 82-yard touchdown down drive then committed the Longhorns' fourth turnover to help TCU put away a 20-13 win Thursday night.
McCoy's scrambling set up the winning field goal in the final game against old rival Texas A&M last year. Texas fans were hoping for a replay from the younger brother for former Longhorns quarterback Colt McCoy against the Horned Frogs.
But McCoy's last pass floated across the middle of the field and was easily intercepted by Sam Carter in the final two minutes to seal TCU's biggest win in the Horned Frogs' first season in the Big 12.
"The ball slipped and floated in the air," McCoy said. "We didn't take care of the ball when we needed to."
Matthew Tucker scored two touchdowns, Jaden Oaberkrom kicked two field goals and TCU's defense forced four turnovers, three by Ash. TCU (7-4, 4-4) dominated the line of scrimmage, running the ball 48 times and passing just 10.
The Horned Frogs had two interceptions inside their own 10 to kill Texas drives and picked up a fumble by Ash to set up Tucker's second touchdown.
"We had to bring the fight to them," TCU safety Jason Verrett said.
Although Texas (8-3, 5-3) has been a Thanksgiving regular since playing its first game on the holiday in 1895, those contests were usually against Texas A&M. But that rivalry broke apart when the Aggies left the Big 12 for the Southeastern Conference after last season.
So the Big 12 sent TCU to Austin this year and the Horned Frogs pushed around the Longhorns at the line of scrimmage and harassed Ash into one of the worst games of his career.
A touchdown by Jeremy Hills pulled Texas within a touchdown with just over three minutes left. But after Texas forced the Horned Frogs to punt, McCoy committed the final turnover.
Texas coach Mack Brown was already preparing for overtime before the turnover.
"Case did a great job, got us back in the game and gave us a chance to win. I actually thought we'd drive down and score," Brown said.
TCU rushed for 217 yards, with a team-high 77 from freshman quarterback Trevone Boykin, and recorded its first win over a ranked opponent this season. TCU linebacker Kenny Cain had 14 tackles.
The Horned Frogs have had to slug their way through their first Big 12 season. They were 4-0 before starting quarterback Casey Pachall was arrested on suspicion of driving while intoxicated, got suspended and then left school for treatment at an inpatient rehabilitation facility.
TCU turned to Boykin and the freshman was coolly effective against the Longhorns, scrambling for big yards on broken plays and called runs after ball fakes.
TCU's first scoring drive started with Boykin throwing out of his own end zone to direct a 94-yard march to Tucker's first touchdown. Tucker was originally ruled down on the 1 but the call was overturned on review to give the Horned Frogs the 7-0 lead.
"We didn't make (Boykin) do much. He didn't have to throw," Brown said. "We didn't force them into doing more than they needed to."
Ash committed two turnovers in the second quarter, throwing an interception on the TCU goal line and coughing up a fumble at the Texas 16 when the ball simply slipped out of his hand as he pulled back to throw. The fumble set up a Tucker's second touchdown, a 1-yard run that put the Horned Frogs ahead 14-3.
At that point, Texas briefly pulled Ash for McCoy, who had rallied Texas to a road win at Kansas. But McCoy couldn't move the Longhorns late in the half and Ash started the third quarter.
Oaberkrom, who missed an early 33-yard attempt, kicked field goals of 18 and 41 yards in the second half to push TCU's lead to 20-6.
"I'm disappointed we couldn't get it done for the seniors," Texas freshman running back Johnathan Gray said. "It hurts quite a bit."