Since Mack Brown has been coaching Texas against Oklahoma's Bob Stoops, success in the Red River Rivalry has boiled down to one telltale statistic.

Without fail, the team that rushes for the most yards wins. Not since 1997, when John Mackovic and John Blake were on the sidelines, has a team failed to win when having an advantage in the rushing department.

"That's just how it's been going the past 10 or 11 years. You definitely have to run the ball," Oklahoma tailback DeMarco Murray said. "I do know that. I'm sure all the coaches know that. We have to take care of the ball and run the ball. If we do those two things, we have a pretty good chance to win the game."

Here comes the tricky part. Neither eighth-ranked Oklahoma (4-0) nor No. 21 Texas (3-1, 1-0 Big 12) has been able to establish a consistent ground game this season. And both have been unexpectedly gashed by opposing rushers.

Murray started the season with a career-best 208-yard outing against Utah State, but he's been averaging only 3.3 yards per carry since then. The Sooners' defense, usually one of the nation's top run stuffers, is giving up 177.5 yards per game and ranks 93rd in the country.

The Longhorns have had their problems, too.

After losing the BCS title game, Brown set out to develop a power rushing attack in spring drills and training camp. It wasn't supposed to replace the passing attack, but was supposed to get Texas the tough yards when it needed them most.

Through four games, the Longhorns have yet to produce a 70-yard rusher while burning through ineffective tailbacks. Cody Johnson started the first game, then Texas went to Tre' Newton only to next try Fozzy Whittaker. He may start again Saturday, but the Longhorns are now starting to explore how to best use speedy D.J. Monroe.

Texas' defense had been the best in the nation, allowing just 44 yards per game against three spread offenses, before UCLA accumulated 264 yards on the ground in a 34-12 win on the Longhorns' home field last week.

The question is which team can get its act together best in time for Saturday's game at the Cotton Bowl in Dallas.

"We're just a little out of kilter. We're not as clean, not as physical and the team we're playing is awfully good at run defense," Sooners offensive coordinator Kevin Wilson said. "They struggled last week but it was an option-oriented attack with a running quarterback, and that's a different style than we're going to throw at them."

Oklahoma had minus-16 yards rushing in a 16-13 loss to Texas last season, when Stoops points out that two NFL-bound tight ends and a few linemen were injured. But none of those players are with the Sooners this year, either.

Wilson said this year's line hasn't done well enough knocking defenders off the line of scrimmage and finishing blocks, relying more on quick footwork than a size advantage. Murray suggested he's also been too fast hitting the hole and failing to let blocks develop before running into contact.

"When we've run the ball, we're getting negative and zero and one (yard) too much instead of three, four, five and getting it more on schedule," Wilson said.

"We've got to keep working at it. We're still making some strides. We're a long way off. We've got to be much more physical. Whether it's scheme or personnel or performance, we need to run the ball a lot better."

Both teams have struggled with poor alignment and missed tackles on defense.

Oklahoma blamed its struggles two weeks ago on Air Force's unique rushing attack that leads the nation in production, yet Cincinnati's Isaiah Pead ran for 169 yards against the Sooners just last week.

The Longhorns? They counted 15 missed tackles that led to 92 additional yards rushing, plus 18 missed assignments, in the UCLA loss.

"We've got to do a better job of motivating our players and getting them in the right spots," Longhorns defensive coordinator Will Muschamp said.

Murray said he certainly doesn't expect an easy day Saturday just because Texas struggled against UCLA.

"They had a little hiccup last week, but I know they'll be fired up to play this game, just like we will," Murray said. "They could be 0-5, we could be 0-5 and we'll play the best game we can come this week."


AP Sports Writer Jim Vertuno contributed to this report from Austin, Texas.