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Just when it seemed the Red River Rivalry couldn't get much worse for No. 15 Texas, a meaningless fourth-down play became a critical point in the Longhorns' season.

Facing a 41-point deficit, starting quarterback David Ash was smashed by Oklahoma's Chuka Ndulue after releasing an incomplete pass and didn't return in the Longhorns' 63-21 loss to the rival Sooners on Saturday.

Coach Mack Brown provided no update on Ash's status, but he had a bruised welt on his injured left wrist when he came off the field pointing to the sky with his right hand.

"It's just unacceptable for Texas to lose like that to Oklahoma, much less anybody, and especially two years in a row," said Brown, whose team has lost by a combined 118-38 margin the past two Red River Rivalries.

"I'm disappointed for our coaches, our fans and our players because that's not who we are."

Damien Williams broke off a 95-yard touchdown run for the longest rush in the rivalry's history, Blake Bell powered his way in for four TDs as Oklahoma rolled.

Bob Stoops is now 9-5 against Brown and responsible for three of Oklahoma's five most lopsided wins over Texas — and that doesn't include last year's 55-17 clobbering.

Put this one right up there with 65-13 in 2003 and 63-14 in 2000, both seasons when the Sooners played for the national championship.

"It's in the same ballpark," Stoops said, trying to rank his glut of triumphs against Texas. "If we'd have left our (starting) defense out there, I don't think the end would have been like it was. It would have been right there with those.

"Those are pretty special ones, and this definitely is right there with them."

Case McCoy relieved Ash and threw late touchdown passes to Mike Davis and John Harris against the Sooners' backups, the last one coming after the Longhorns called timeout to run one last play.

Brown called his offense "inept" and questioned why his defense didn't make as many plays as he's used to seeing from them. Texas was outgained 677-289 and gave up 343 yards rushing. A defense expected to be a strong point for the team has now given up 1,186 yards rushing in the past five weeks.

"We couldn't stop the run. When you can't stop the run, things get ugly real quick," said Alex Okafor, the Longhorns' defensive end and NFL prospect. "It's been like that all season. We've got to find a way to stop it."

Carrington Byndom provided the lone defensive highlight by returning an interception for a touchdown just after halftime, but it didn't create a spark for the Longhorns. Brown warned that Baylor, the nation's No. 2 offense, comes to Austin next week.

"We can't sit around and feel sorry for ourselves. We're sitting here exactly where we were this time last year, but we've got to go finish better than we did last year," Brown said.

The Longhorns had been off to a promising start and Ash had shown marked improvement as the entrenched starter, completing at least 70 percent of his passes in every game this season. He went 13 for 29 in this one with 113 yards passing and two interceptions.

Counterpart Landry Jones threw for 321 yards and two touchdowns, and for the third straight time got to slap on his head the Golden Hat trophy that goes to the winner. He entered rare territory, breaking Steve Davis' record for wins at the school and becoming just the fourth Sooners QB to beat Texas three times.

"Just the game of football is great, but this game in particular, there's something about it," Jones said.

Fullback Trey Millard had a career-best 119 yards receiving, including a 73-yard catch that was one of two early back-breaking plays by the Sooners (4-1, 2-1 Big 12).

After Texas' second of four straight three-and-outs to start the game, Williams zipped through a hole on the right side of the line and got a smashing block from receiver Kenny Stills against Quandre Diggs to clear the way for the longest run in the rivalry's 107 games.

Millard then went hurdling over safety Mykkele Thompson to turn a short pass into a 73-yard gain and set up Bell's third score to make it 27-2.

The Longhorns were being outgained 314 yards to 14 at that point.

All that kept Texas from a completely inept first half was a botched extra-point snap by the Sooners after their first touchdown, allowing Chris Whaley to block Michael Hunnicutt's kick and Diggs to return it for a 2-point conversion.

Even when there was a tiny glimmer of hope for the Longhorns, Oklahoma quickly snuffed it out.

Davis provided the first Texas first down with a leaping 31-yard catch along the sideline, getting up and pumping his arms to try to get his teammates fired up. But on the very next play, Ash tried to go deep again and Aaron Colvin picked off his pass.

The Sooners didn't score on that drive, but Justin Brown downed Tress Way's punt at the 1-yard line and a horde of Oklahoma players converged to take down Joe Bergeron for a safety on the next play. Williams ran right through the Longhorns to set up Bell's fourth touchdown run — a 1-yarder that had him backing his way in for a 36-2 advantage.

"The offense was rolling. When they're rolling and we're getting three-and-outs, it's going to be a long day for whoever we're playing," Sooners defensive end David King said. "That's what happened. We put up 30 points in the first half and there was no coming back."