Freshman post player Zeke Nnaji recorded his seventh double-double as Arizona used balanced scoring and dominant rebounding to beat No. 20 Colorado 75-54 on Saturday afternoon in Tucson, Ariz.

Josh Green and Dylan Smith each scored 13 points for the Wildcats (13-5, 3-2 Pac-12), who won their first game in four tries against a ranked team. Nnaji had 12 points and a game-high 12 rebounds, including seven off the offensive glass to match Colorado's team total.

Arizona freshman point guard Nico Mannion had 12 points with a career-high seven rebounds and five assists. Max Hazzard scored nine off the bench, hitting 3 of 6 3-point shots.

The Buffaloes (14-4, 3-2) fell behind early because of 32 percent first-half shooting and never made a serious run. They were led by McKinley Wright IV, who scored 15 points. D'Shawn Schwartz contributed 12 points, and Tyler Bey added nine.

Colorado is 0-8 in Arizona's McKale Center since joining the Pac-12 for the 2011-12 season.

Arizona led 34-23 at halftime and was up by double digits for the final 18:04 of the game. The Wildcats' 39-25 rebounding edge helped Arizona pile on after the break.

Backup power forward Ira Lee twice had dunks for a 20-point lead late in the game, and his put-back with 4:19 to go gave the Wildcats a 69-48 advantage.

Arizona used a 9-0 run, capped by jumper from Jemarl Baker, for a 14-10 lead with about nine minutes to go before halftime. At that point, Colorado was 3 of 15 from the field, including 1 of 9 from 3-point range.

The Buffaloes' cold streak continued as the Wildcats extended their lead to 21-12 with a 7-0 run and went up 34-20 in the final minute when Smith scored five points in 14 seconds on a transition 3-pointer and a layup after his steal.

Colorado closed to 34-23 at intermission when Wright banked in a contested 3-pointer at the buzzer.

Arizona played without starting center Chase Jeter (8.1 points, 5.3 rebounds per game) for the second consecutive game due to back spasms.