Dusan Ristic had 15 points and eight rebounds and Dylan Smith added 13 points for Arizona (17-4, 7-1 Pac-12). The Wildcats have won 14 of 15 and five in a row since losing to Colorado in Boulder on Jan. 6.
George King had 22 points and McKinley Wright IV had 15 points and seven assists for the Buffaloes (12-9, 4-5), who had won four of six starting with a sweep of the Arizona schools.
Arizona, 11th in NCAA Division I with a 50.3 field-goal percentage entering the game, shot 53.1 percent from the floor, making 16 of 23 field-goal attempts in the second half after falling into a 10-point, first-half deficit.
The Wildcats made their first 20 free-throw attempts and hit 22 of 23 overall. Ayton hit all 12 of his foul shots.
Wright capped a 9-0 run with a 3-pointer to bring the Buffaloes to within 60-59 with 7:09 to play before Arizona scored the next five points to regain control.
Parker Jackson-Cartwright's 3-pointer, his only points in the game, gave Arizona a 78-70 lead with one minute remaining.
Tyler Bey had 11 points and seven rebounds for the Buffaloes.
Smith started in place of Rawle Alkins, the Wildcats' third-leading scorer at 14.6 points a game. Alkins has missed two of the past three games because of right foot soreness. He had foot surgery in the offseason.
King, Wright and Dominique Collier made 3-pointers in the first seven minutes when Colorado scored the first eight points and 14 of the first 18 for a quick early lead.
Arizona missed its first six field-goal attempts and 13 of its first 15 before using eight points from Ayton and seven apiece from Smith and Trier to tie it at 30 at the half.
Smith's 3-pointer in the first minute of the second half gave Arizona its first lead and began a decisive 15-4 burst for a 45-34 lead.
Arizona is 81-2 at home since the 2012-13 season and 67-9 in Pac-12 games under coach Sean Miller.
Colorado has not beaten Arizona in Tucson in Miller's nine seasons.
--Field Level Media
Colorado | Arizona | |
George King 22 | Scoring | Allonzo Trier 23 |
McKinley Wright IV 7 | Assists | Parker Jackson-Cartwright 4 |
Tyler Bey 7 | Rebounds | Dusan Ristic 8 |
Dominique Collier 3 | Free Throws Made | DeAndre Ayton 12 |
Tyler Bey 3 | Steals | Dylan Smith 1 |
Tyler Bey 1 | Blocks | DeAndre Ayton 2 |