AUSTIN, Texas (AP) -- Leading 7-0 late in the first half against No. 15 Texas, New Mexico State found itself in the unlikeliest of positions in front of nearly 100,000 fans on the road.
But that brief spark of excitement in a new season under a new coach quickly turned into the same old result. A rout.
David Ash threw four touchdown passes and ran for another as the Longhorns shook off a slow start and rolled to a 56-7 win Saturday night, snuffing out the Aggies' early lead with 35 points on 15 plays in the second and third quarters.
"It's a game of momentum and they got momentum on their side. After they got that, (plus) 100,000 screaming fans, it's kind of hard to recover from," New Mexico State linebacker Clint Barnard said.
Ash threw two interceptions in the second quarter and the Longhorns' new up-tempo offense stalled as the Aggies grabbed the lead. Ash then connected on touchdown passes of 54 and 66 yards to John Harris and Daje Johnson in the final two minutes of the first half.
Still the Aggies were within a touchdown of the Longhorns at halftime.
"That's about as good as would've hoped for coming into that," first-year Aggies coach Doug Martin said. "We let it get away from us in the second half. We gave up too many big plays. We had some mental breakdowns that really hurt us."
In the third quarter, Ash turned a scramble into a 55-yard touchdown and passed to Malcolm Brown for a 74-yard score. Once it got rolling, Texas piled up a school-record 715 total yards with Ash accounting for 434.
"We started off obviously slow," Ash said. "You feel that momentum shift when things start rolling. We're a good team when that starts happening."
Andrew McDonald was 32-of-46 passing with one touchdown for New Mexico State but also had two turnovers for the Aggies (0-1), who went 1-11 last season.
"We had too many turnovers and they all emanated from the quarterback position. Andrew's got to do a better job of taking care of the football," Martin said.
Texas came into the season touting its new offense and the new confidence displayed in training camp by Ash, who spent the last two years under constant threat of being pulled for Case McCoy. Even coach Mack Brown had said his team is ready to challenge for the Big 12 title and return among the nation's elite.
But despite the new enthusiasm and bravado that comes with 19 returning starters, almost nothing went right early. Ash looked like the same quarterback of the last two years: talented but prone to mistakes.
The Longhorns had three first-half turnovers, two by Ash, and some frustrated fans booed when New Mexico State scored on a pass from McDonald to Joshua Bowen.
"I think everyone else in the stadium might have been shocked, but we weren't," Bowen said.
Ash, who last year might have collapsed after the early turnover or been pulled from the game, then found Harris open on the sideline for Texas' first touchdown with 1:48 left in the half. After Texas used three quick timeouts to force New Mexico State to punt, Ash connected with Johnson across the middle and the receiver sped away from five defenders for another long score.
With momentum swung to Texas, New Mexico State gambled with an onside kick to open the second half. The Longhorns recovered and Johnson scored again four plays later, scooting around the left side on a sweep for a 21-7 Texas lead that broke the game open.
New Mexico State couldn't match Texas' speed in the open field. Ash's dash through the secondary and his long scoring pass to Brown turned it into a rout long before Ash connected with Mike Davis for his fourth touchdown pass -- this one a short 25-yarder -- in the fourth quarter.