ESPN College Football

AUSTIN, Texas -- Texas has seen something like this before: A quarterback named McCoy leading a late rally to win, pumping his fists all the way.

From 2006-2009 it was Colt McCoy, who won an NCAA record 45 games. On Saturday night, it was Colt's younger brother Case coming off the bench to help spark the No. 24 Longhorns to a 17-16 win over BYU.

Texas (2-0) pulled ineffective starter Garrett Gilbert in the second quarter and handed the offense to sophomore McCoy and freshman quarterback David Ash in a rotation that flipped a game the Cougars (1-1) were dominating.

McCoy and Ash combined to hit 9 of 11 passes for 92 yards and Ash also rushed for 39 yards. McCoy carried the load on Texas' winning drive, twice connecting with Jaxon Shipley for big gains before Cody Johnson punched in his second touchdown for the lead with 8:46 to play.

"When Case came in, he played a real leadership role for us," said Shipley, a freshman who is the younger brother of Texas' career receptions leader Jordan Shipley.

"He was pumping us up, telling us he was going to lead us to victory," Shipley said.

"When I was named the backup, I knew that you're always one play away," McCoy said. "I felt our team rallied around me and David."

BYU dominated Texas early but wilted under the 98-degree temperatures and Texas' punishing running game in the second half. The Longhorns' D.J. Monroe had two long runs in Texas' first touchdown drive and Malcolm Brown led the Longhorns with 68 yards rushing, most of it in the second half.

Playing its first season as a football independent, BYU squandered a 13-0 lead and a chance to get a second straight road win in one of the nation's power conferences. The Cougars rallied from 13 points down in the fourth quarter a week earlier to beat Mississippi.

Jake Heaps led BYU (1-1)with 235 yards passing with one touchdown and two interceptions. Justin Sorensen kicked field goals of 30, 33 and 32 yards.

"It's tough to lose a game like this," especially when we let someone come back and beat us," Heaps said. "It's uncharacteristic of our football team."

Texas' new QB duo could push Gilbert out of the starting role.

Gilbert won a four-way battle in training camp to keep the starting job after throwing 17 interceptions in Texas' 5-7 season in 2010. But he was just 2 of 8 for eight yards with two interceptions and was lustily booed by the home crowd.

After the second interception, Heaps drove BYU 97 yards on 13 plays for the only touchdown of the half, a 6-yard toss to Ross Apo for a 13-0 Cougars lead.

"We needed a spark," Texas first-year offensive coordinator Bryan Harsin said. "That's why we made the change."

It didn't work right away. The McCoy-Ash rotation failed to pick up a first down on its first series.

The Longhorns finally scored after Heaps threw an interception on the BYU 29 and Justin Tucker kicked a short field goal to make it 13-3 at halftime.

BYU held Texas to just 88 total yards and three first downs in the first half. The Longhorns looked stuck in a game like their home losses to UCLA and Iowa State last season.

"This is the same place we were last year and didn't respond well," Texas coach Mack Brown said. "This team wouldn't have won this game last year."

Texas stuck with the backup QBs to start the third quarter and scored on its first possession. Ash ran the option and the Longhorns drove 68 yards -- all on the ground -- to set up Johnson's 1-yard touchdown run that made it 13-10.

Monroe provided the big play on the drive with a 29-yard run and the BYU defense, so stout up to that point, looked helpless against Texas' power and speed rushers.

The boos that rained down in the second quarter quickly turned into chants of "Texas Fight!"

BYU coach Bronco Mendenhall was impressed with Ash's running that began turning the game in Texas' favor.

"He played with a lot of heart, toughness, and I think it made a difference in helping them with time of possession," Mendenhall said.

BYU still led 16-10 after Sorensen's third field goal, but the Cougars were clearly unsettled.

McCoy led an 8-play scoring drive that started at the Texas 48, connecting twice with Shipley for big gains before Johnson scored on a 4-yard run up the middle that put Texas ahead for the first time with 8:46 to play. Shipley had to make both catches with defenders draped all over him.

The Longhorns put the game away with a trick play reverse pass from Shipley to Ash that picked up a key third down with under 3 minutes to play.

Brown wouldn't say after the game if he was disappointed in the loud boos directed at Gilbert or if he'll stick with the McCoy-Ash rotation next week when the Longhorns travel to UCLA.

"I want them (fans) coming and they expressed their opinion," Brown said. "We'll talk about (the quarterbacks) tomorrow. I'm just happy we won."