Allonzo Trier scored eight of his team-high 29 points in overtime to lead Arizona past UNLV, 91-88, on Saturday night.
Deandre Ayton had 28 points and 10 rebounds, while Parker Jackson-Cartwright scored 12 points for the Wildcats.
Arizona (5-3) hit 18 of 29 (62.1 percent) in the second half.
Brandon McCoy led UNLV (6-2) with a game-high 33 points and 10 rebounds, while Shakur Juiston added 21 points and nine rebounds.
Ayton came into the weekend one of just seven players in the nation averaging at least 15 points and 10 rebounds per game, while shootting 60 percent or better from the field. Ayton is one of just two freshmen in college basketball with the feat, ironically, along with UNLV's McCoy.
After a poor showing in the first half, the Wildcats came out of the locker room sizzling, hitting three 3-pointers during a 13-8 run that carved into UNLV's lead, making it 49-43 less than four minutes into the second half.
Arizona took its first lead of the game at the 9:42 mark, when Dylan Smith converted a 3-point play. The teams traded baskets until Trier hit three straight buckets for the Wildcats, giving them a 67-64 lead with a little more than six minutes left in the game.
The Rebels opened the game with the hot hand, hitting 54.5 percent (6 of 11) from the field over the first eight minutes, while the Wildcats hit a mere 22.2 percent (4 of 18). UNLV led 41-30 at halftime after shooting 17 for 30 (56.7 percent), and outrebounding the Wildcats 24-16. Arizona shot just 35 percent (14 of 40) over the first 20 minutes.
Arizona: After becoming the first team in 31 years to drop from No. 2 all the way out of the Top 25 poll, after a disastrous trip to the Bahamas, the Wildcats received 34 votes last week and look for a possible return to the poll after going 2-0 this week. Arizona had been ranked in every AP Top 25 poll, counting preseason and weekly polls, since the beginning of the 2012-13 season.
UNLV: The Runnin' Rebels are now 8-2 all-time versus Arizona at home, including 4-2 at the Thomas & Mack Center. UNLV is 12-9 against Arizona all-time and 61-61 against teams that currently make up the Pac-12 Conference. The Runnin' Rebels defeated Utah, 85-58, on Nov. 22.
Arizona plays No. 9 Texas A&M on Tuesday, in the Valley of the Sun Shootout in Phoenix.
UNLV plays Oral Roberts on Tuesday, at the MGM Grand Garden