Arizona guard Rawle Alkins (1) gets the from-behind block on USC guard Elijah Stewart (30) in the first half of their Pac-12 game at McKale Center, Thursday, Feb. 23, 2017, Tucson, Ariz. Kelly Presnell / Arizona Daily Star

Kelly Presnell / Arizona Daily Star

Arizona couldn’t stop USC from shooting 52.9 percent Thursday, but the Wildcats found a pretty good workaround.

In an 90-77 win over the Trojans at McKale Center, UA hit 11 of 20 3-pointers and shot 50.8 percent overall – while collecting 23 points off 14 USC turnovers.

The 11 3-pointers were the most Arizona has made in a Pac-12 game this season and second most overall; the Wildcats hit 13 of 24 at Missouri on Dec. 10.

Allonzo Trier led the Wildcats with a season-high 25 points on 7-for-11 shooting while Rawle Alkins had 12 and Dusan Ristic 10. Lauri Markkanen had 11 points and seven rebounds,

The win, UA’s 21st straight at McKale Center and fifth in a row, moved the Wildcats to 26-3 overall and 15-1 in the Pac-12, where they remain a game ahead of Oregon. USC dropped to 21-7 and 8-7.

The fourth-ranked Wildcats will next host No. 5 UCLA in a rare Top 5 showdown on Saturday at 6:15 p.m. in McKale Center.

UA trailed by up to nine in the first half, and after the Wildcats led 44-39 at halftime, USC pulled within two points early in the second half, 51-49, after Bennie Boatwright hit a pair of 3-pointers early in the second half. Boatwright led USC in scoring with 23 points.

But the Wildcats went on a 15-4 run to take control of the game. At the end of the run, they led 66-53, after Trier made a layup and then scored again after a quick turnover in the USC backcourt.

The Wildcats shot 63.2 percent through the first 12 minutes of the second half, continuing a blistering pace set late in the first half. They shot only 29.4 percent through the first 9:58 of the game.

Over the final 2:11 of the first half, Arizona finished with a flurry of four 3-pointers over the to pull out of an early slump and take its 44-39 halftime lead.

The Wildcats allowed USC to shoot 58.3 percent through the first 17 minutes of the game and trailed by up to nine points before making a late run in the half. The Wildcats went on a 6-0 run to take a 38-37 lead with 1:43 left and gained their final first-half edge after Trier sank a 3-pointer as time expired.

UA pulled out of its last nine-point hole with an unusual four-point swing: Markkanen sank a 10-foot shot while Chance Comanche was fouled on the same play, then going to the free-throw line to hit both ends of a one-and-one. That made it 33-28 with 4:19 left and UA kept going from there.

Trier finished the half with 10 points to lead UA, which shot 45.7 percent from the field after shooting under 30 percent for the first 10 minutes.

But defense was an issue for the Wildcats throughout the half: USC shot 57.1 percent from the field, while Bennie Boatwright and Jordan McLaughlin each had nine points to lead the Trojans.

While Arizona took an early 13-8 lead, the Trojans went on a 18-4 run to take leads of nine points midway through the first half, beating the Wildcats inside and shooting jumpers over their defense.

One of the few breaks they had during that stretch was when USC’s Elijah Stewart raced through the UA defense for a dunk – but was called for a technical foul for hanging too long on the rim.

With Kadeem Allen and Dusan Ristic both coming off injuries, and sophomore Comanche playing well in Ristic’s absence last week in Washington, Arizona coach Sean Miller shook up his starting lineup. He went with Parker Jackson-Cartwright, Allen and Trier on the perimeter, with Comanche and Markkanen inside.

Miller said on his pregame radio interview that both Allen and Ristic had progressed. While Allen started, Ristic played eight minutes off the bench in the first half.

“They’re healthy and ready to play and contribute,” he said.

Both teams struggled early in the game, with UA missing its first four shots and Trier committing a turnover before Allen scored to tie the game at 2. UA took a 13-8 lead with 12 minutes left before McLaughlin tied it up at 13 with two-point and 3-point jumpers at the beginning of the Trojans’ run.

The Wildcats shot just 29.4 percent before 90 Alkins made a layup to cut UA’s lead to 17-15 with 10 minutes left in the half.