Bruins enjoy the show

It was a play of instinct, a pass of 50 feet from Darren Collison to Michael Roll and a touch pass from Roll to Arron Afflalo, setting up a layup by Afflalo as the buzzer sounded for halftime.

“No, we don’t practice that,” Afflalo said. “It’s just fun.”

UCLA, seeded second in the NCAA West Regional, had nothing but fun Thursday in its 70-42 win over 15th-seeded Weber State at Arco Arena.

And the only part that wasn’t fun for the Bruins, who will face seventh-seeded Indiana on Saturday, was when center Lorenzo Mata threw up midway through the first half.

“That’s what he said he ate?” said UCLA Coach Ben Howland, hearing that the problem was two peanut butter and jelly sandwiches. “All they eat is junk food.”

The crackling play that ended the first half and gave the Bruins a 37-19 halftime lead was all instinct.

“I was afraid I’d thrown the pass too far,” Collison said.

“I saw the ball coming and saw Arron open,” Roll said.

“That’s what basketball players do,” Afflalo said. “Make plays.”

With his game highs of 22 points and eight rebounds in 32 minutes, Afflalo regained his grasp of the game that had seemed to slip from his hands a week ago. After taking only seven shots and scoring a season-low three points in an overtime loss to California in the quarterfinals of the Pacific 10 tournament, Afflalo was questioned as he had never been in his three-year UCLA career.

Also trying to learn where his game stood was Bruins point guard Collison.

The sophomore had sprained his left ankle in practice Tuesday evening, just before UCLA (27-5) set forth on this tournament journey.

On UCLA’s first offensive play Collison missed a three-pointer, then Afflalo did too. Weber State (20-12), winner of the Big Sky Conference, took a 2-0 lead. The Wildcats would get another advantage after an 8-0 run put them ahead, 10-9.

It was then that UCLA’s Luc Richard Mbah a Moute picked up his second foul with 9:15 left in the first half. A few moments later Mata was doubled over on the UCLA bench. And so the Bruins staggered for a moment, but from that adversity came surprising help from their often overlooked bench.

Roll made back-to-back three-point shots that pushed the Bruins from a 15-14 lead to a 21-14 advantage. Freshman James Keefe, who has barely scored a point a game and rebounded less than that, had three enthusiastic rebounds, a basket and an assist.

“I can’t say enough about James Keefe,” Howland said.

And then UCLA’s usual stars also found their tempo.

Collison made consecutive layups to give UCLA a 25-14 lead. Mata, done with his stomach upheavals, came back just in time to dunk a rebound. “He’s got a lot of guts,” Howland said, not intending any double meaning.

Afflalo, stricken with some sort of shooting shyness in that Cal loss, broke out of his doldrums with two three-pointers in succession and then gave himself a little chest thump.

And the end of the half came with the highlight dash. “That kind of play always gives you a boost,” Afflalo said.

“I was watching it from the bench,” said sophomore Josh Shipp, who had 12 points, “and it got me jazzed.”

Even the queasy Mata, who also took an Afflalo pass off his face, was running at top speed off the court.

Against a team unaccustomed to UCLA’s brand of defense, Weber State shot only 26.3% from the field in the first half and was outrebounded, 20-12.

Weber State star David Patten, who is from Placentia and who once played for Pepperdine, was treated unkindly in the first 20 minutes. He missed all four shots, had one blocked by Mata and committed two turnovers.

There was no letup from the Bruins in the second half. Collison started things with a three-pointer and Mata followed with a dunk and then another. Afflalo made a three-pointer, and it was 47-23 before the first timeout of the second half. This rout wasn’t going to be undone.

It also wasn’t going to be extravagantly celebrated either. Afflalo said, “One game is nothing to get too excited about. It’s not a trend yet.”

Said Collison, who had 14 points and eight assists: “Unfortunately the tournament doesn’t keep going like this. The way it’s built, every game gets tougher instead of easier.”

And his ankle hurt, he said. “The adrenaline made the pain go away during the game,” Collison said. “Not now.”

Weber State Coach Randy Rahe said he was impressed with the Bruins. “I think this team, the way they play and how well-coached they are, they are built for tournament success.”

That’s too soon to tell, Afflalo insisted. “Let’s just see how it goes,” he said.

diane.pucin@latimes.com