Arizona Wildcats guard Rawle Alkins (1) jumps for a basket as UCLA Bruins guard Isaac Hamilton (10) defends in the first half during a game at Pauley Pavilion on Saturday, Jan. 21, 2017. Mamta Popat / Arizona Daily Star

Mamta Popat / Arizona Daily Star

LOS ANGELES – In his first game back after a 19-game suspension for a positive performance-enhancing drug test, Allonzo Trier helped prop up the Arizona defense while the Wildcats held on for a 96-85 upset of UCLA at sold-out Pauley Pavilion.

The No. 3-ranked Bruins had not lost at home all season, but couldn’t take the lead back after losing one late in the first half, even as they cut Arizona leads of up to 14 points early in the second half to just four.

UCLA shot 44 percent from the field but was outshot and outrebounded by UA, which had a 42-33 rebounding edge and shot 50 percent from the field.

Arizona had six players scoring in double figures, led by Kobi Simmons, who had 20 points on 6-for-14 shooting. Lauri Markkanen added 18 points and seven rebounds.

Trier had 12 points on 4-for-10 shooting, plus seven rebounds and four assists.

Trier didn’t enter the game until the first media timeout but finished the first half with six points that included a coast-to-coast layup just before the halftime buzzer, while Arizona took a 48-37 halftime lead.

In the first half, Markkanen led the Wildcats  with 10 points and four rebounds, while Simmons also had 10 points.

UCLA was led in the first half by Lonzo Ball, who had 15 points and three assists, but the Wildcats outshot the Bruins, 51.5 percent to 44.1 percent.

Ball finished with 24 points, eight assists and six rebounds.

Ball engineered a characteristically fast tempo early in the game, with UCLA taking an early 16-10 lead when Ball fired a three-quarter-court assist to Bryce Alford for an easy basket.

UCLA made 7 of 13 shots at the first media timeout, but the Wildcats’ defense began to kick in at that point and Arizona gradually moved ahead to its 11-point margin.

UA said it was notified Friday afternoon by the NCAA that Trier had tested negative for any remaining traces of a performance-enhancing drug that led to an eventual 19-game suspension. Trier has been practicing with the Wildcats all season but said in a statement Wednesday that he wouldn’t be allowed to return until he tested clean.

Sportswriter for the Arizona Daily Star covering Arizona Wildcats basketball