LOS ANGELES — Boosted by the return of Allonzo Trier, No. 14 Arizona showed off a potent offense to go along with its swarming defense.
Trier led a late run in the first half and finished with 12 points in his first game of the season, helping the Wildcats topple No. 3 UCLA 96-85 Saturday.
Trier's status was resolved Friday night after he tested negative for a performance-enhancing drug.
The sophomore from Seattle — who averaged nearly 15 points per game last season — had been practicing and traveling with the Wildcats, but the school had refused to say why he wasn't playing.
Trier said this week that he had inadvertently taken a substance with a trace amount of PED in it. He said the NCAA wouldn't allow him to play until his system was completely cleared of the drug.
UCLA fans chanted "steroids" at him. Trier wasn't made available to the media afterward.
"I don't think we win without him," coach Sean Miller said. "It means a lot, especially for this team and his family."
The Wildcats won their 12th in a row, putting up 21 more points than they average. Arizona (18-2, 7-0 Pac-12) has the top-rated defense in the conference.
Kobi Simmons scored 20 points and Lauri Markkanen added 18.
"We've had big goals all along," Markkanen said. "This gives us an extra boost."
So do the Bruins (19-2, 6-2), who hope to be playing for a national championship in April.
"If we want to become great, we've got to play as unselfishly defensively together as we do at the offensive end," UCLA coach Steve Alford said. "You could be awfully special by the time we get to March, but your defense has got to grow."
Lonzo Ball scored 24 points for UCLA, which had its 11-game home winning streak snapped in front of a sellout crowd that included Hall of Famers Kareem Abdul-Jabbar (NBA), Cris Carter (NFL) and Dave Winfield (MLB).
"It's a wakeup call," Ball said. "The places we want to go we have to play defense."
It was the first time the longtime Pac-12 powers faced each other while both were ranked in the top 15 since Jan. 20, 2007, when UCLA won at home.
Simmons scored consecutive baskets that pushed Arizona's lead to 14 points early in the second half.
UCLA's defense faltered as the second half wore on, with the Wildcats scoring on nearly every possession. That prevented the Bruins' speedy transition game from getting going.
They scrambled to get back into it on 3-pointers, with Isaac Hamilton hitting one that drew them to 67-65. Aaron Holiday's 3 left UCLA trailing 72-68 just after Ball picked up his third foul. Three other starters also had three fouls.
Hamilton made two free throws that left UCLA trailing by six with just over a minute to go. But Markkanen dunked off his offensive rebound, got fouled and made the free throw to extend Arizona's lead to 92-83.
The Wildcats controlled the boards, 42-33, and owned a 24-18 edge in second-chance points.
"It's a big win. It means a lot them being ranked number three," Markkanen said. "We knew their transition offense was really tough. We focused on getting back after crashing the offensive glass. It worked extremely well at times."
The Bruins came in averaging a league-best 93.3 points and had been beating opponents by an average of 17.8 points. Arizona's defense was allowing 61.8 points.
Down 29-27, the Wildcats closed the first half on a 21-8 run to lead 48-37 at the break. They hit four 3-pointers in the spurt, including one by Trier, who singlehandedly outscored the Bruins 6-0 to end the half in his first game of the season.
"They have to change up their game plan," Simmons said. "We had another player that they didn't know was coming. That was big."
Ball carried the Bruins in the first half with 15 points. The rest of his teammates shot 9 of 25 from the field.