TUCSON, ARIZ. ? After four victories by an average of 29 points, No. 1 Arizona is ready for a bigger challenge. The Wildcats figure to get one when they play host to eighth-ranked Texas today.

“This is the one we’ve been waiting for,” Arizona’s Rick Anderson said. “This is the first big test.”

The game would have been No. 1 against No. 2 had Texas (5-1) not lost to Notre Dame, 98-92, a week ago. Still, it is a strong matchup of two teams that love to run.

“They are very, very aggressive, both offensively and defensively,” Arizona coach Lute Olson said. “They are the best board team we’ve faced, and they attack the basket best of anybody we’ve faced.”

The Wildcats (4-0) almost certainly won’t have Luke Walton, who sprained his right ankle in practice Monday and was on crutches all week. Freshmen Andre Iguodala and Hassan Adams will split time in Walton’s small forward position.

Arizona shooting guard Salim Stoudamire, bothered by a sore left ankle, expects to play but won’t start. Will Bynum, averaging 13.5 points and shooting 45 percent from 3-point range, will start instead.

The game features two of the nation’s top point guards in Arizona’s Jason Gardner and Texas’ T.J. Ford.

“They are both really quick with the ball and have point-guard mentalities,” Olson said. “A year ago, you would have said with T.J. that he wasn’t as good of a shooter as Jason at the same stage, but he’s worked really hard on his shooting in the offseason. You can see that.”