AUSTIN (AP) _ Chris Mihm remains a constant for Texas. It's the lineup around him that's in flux.

That's not necessarily a bad thing for Texas. In fact, a little variety could be good for the Longhorns, defending Big 12 regular season champions, when they head back to league play Thursday against Baylor.

After four games of starting a smaller lineup to promote quicker ball movement, No. 18 Texas was forced to abandon that strategy for more size before pulling away from Houston 90-80 Sunday night.

Mihm led the Longhorns with 20 points, 13 rebounds and seven blocked shots. The 7-foot center has eight double-doubles this season.

``I think the big lineup has had its downs, but we used it tonight and it helped us defensively,'' Mihm said.

Texas (8-3), which has started a three-guard lineup the past four games, found itself trying to match baskets with the Cougars (6-7) and the score tied 57-57 with 12:23 to play.

That's when Longhorns coach Rick Barnes reverted to using three forwards with a steady rotation of Mihm, Gabe Muoneke, Chris Owens and William Wyatt.

The shift in size and power near the basket sparked a 14-4 run over the next five minutes to put the Longhorns ahead 71-61 with 7:19 to play. Guard Ivan Wagner started the run with a 3-pointer and Mihm and Muoneke ended it with seven straight points in the paint.

Muoneke had 17 points, while Owens added 14 and William Clay 12.

``I probably should have gone to a bigger lineup earlier, but I was concerned we wouldn't flow as good on offense,'' Barnes said. ``(Up front) is where they were beating us.''

Texas' smaller lineup had few troubles scoring early but Houston's frontcourt duo of freshman George Williams and senior Kenny Younger forced Texas to change its attack.

Able to post-up Texas' smaller guards, Williams had 23 points and 12 rebounds. Gee Gervin had 20 points for Houston, while Younger added 16 _ 12 in the first half.

``We had answers, so that was the key,'' Barnes said. ``There's no question that we can go big when we have to.''

``They're physical and they're good with their size,'' Williams said. ``They move the ball well and they're smart. Banging wears you down over the course of a game.''

The Longhorns' smaller lineup had success early against Houston and used a 14-4 run to take a 24-14 lead with 13:04 left in the first half.

Houston then tightened up defensively. The Cougars forced 10 turnovers in the first half and held the Longhorns without a field goal over the next six minutes to pull within 30-25. Texas recovered from the drought to lead 40-37 after Chris McColpin's 3-pointer.

Houston opened the second half with a 6-0 run to grab a 43-40 lead and the teams stayed within three points of each other before Texas' decisive run.

Texas led 84-72 with 42 seconds left before Roy Spears hit a 3-pointer and Gervin made three consecutive foul shots to pull the Cougars back to 84-78. Muoneke then hit a driving layup, Wagner made one of two free throws and Owens converted a 3-point play to close the scoring.

``We played well enough to win, but we didn't get contributions from everybody coming off the bench,'' said Houston coach Clyde Drexler.

``We had walk-ons coming in and it's hard to keep up with NBA players with walk-ons.''

Texas shot 52 percent, the sixth time this season the Longhorns have made more than half their shots. Texas held Houston to 38 percent and outrebounded the Cougars 46-39.