TUCSON — Allonzo Trier scored a season-high 25 points, including four 3-pointers, and No. 4 Arizona beat USC 90-77 on Thursday night to stay alone atop the Pac-12 and set up a Saturday showdown against No. 5 UCLA.
Rawle Alkins added 12 points and Lauri Markkanen had 11 for the Wildcats (26-3, 15-1) in Arizona's 21st consecutive home win.
Bennie Boatwright scored 23 points and Chimezie Metu had 15 for the Trojans (22-7, 8-7), who lost their third in a row — to the top three teams in the conference (Arizona, Oregon and UCLA).
The Wildcats closed the first half with a 12-2 run and were up by as many as 16 points in the second half.
Arizona made 11 3-pointers in 20 attempts, its most 3s in a Pac-12 game this season.
After shooting under 30 percent for the first 10 minutes of the game, the Wildcats got the offense rolling and finished at 53 percent from the field.
USC shot 51 percent but 3-pointers and turnovers were the difference. Arizona had 23 points off the Trojans' 14 turnovers to USC's nine points off eight turnovers.
The Wildcats, down by as many as nine points early, finished the first half on a 12-2 run, all of the points coming on 3-pointers — two by Kobi Simmons and two by Trier. Trier's 3 at the buzzer capped the outburst and put the Wildcats up 44-39.
After the Trojans cut the lead 51-41, Arizona outscored USC 20-6 over a 4-minute span to go up 71-55 on Dusan Ristic's inside basket with 9:36 to play. Another 7-1 spurt, punctuated by Parker Jackson-Cartwright's 3, gave Arizona a 78-62 lead with 5:03 left.
The Trojans made a late charge with an 11-2 run. Boatwright's two free throws with 1:49 to play cutting the lead to 81-73. But Markkanen scored on a driving floater, Trier made two free throws and the Wildcats sealed the win.
The first-half offense was kick-started by what amounted to a four-point play. Markkanen scored and, at virtually the same time, teammate Chance Comanche was fouled. Comanche made both free throws and Arizona sliced the USC lead to 35-30 with 4:08 left before halftime.
Arizona took care of the required business without looking ahead to the Bruins. Now comes a UCLA team that Arizona beat in Los Angeles earlier this season.
USC is fading in the Pac-12 standings but still harbors strong NCAA Tournament hopes.
The Wildcats will try to finish the season 15-0 at home in their showdown with UCLA on Saturday night.
Overall, they have won 21 in a row at McKale Center dating to last season's home loss to Oregon. That was the only loss at home for Arizona in 71 games.
With another sellout crowd, attendance at McKale topped 9 million since the building was built in 1973.
USC: The Trojans have two days off before playing at Arizona State on Sunday night.
Arizona: The Wildcats host No. 5 UCLA in a major Pac-12 showdown on Saturday night.