TUCSON, Ariz. -- Arizona survived a replay review at the end of the regulation, then beat Colorado 92-83 in overtime Thursday in the Pac-12 opener for both teams Thursday night.
The third-ranked Wildcats (14-0) remains one of four unbeaten teams in college basketball, the others being Duke, Michigan and Wyoming.
Colorado nearly won in regulation as Sabatino Chen banked in a 3-pointer from the top of the key at the buzzer, but officials waved off the basket after looking at courtside replays for about three minutes.
Arizona senior point guard Mark Lyons scored 24 points, including the tying free throws late in regulation.
The Buffaloes (10-3) led by 16 points with 12:42 to play. Arizona whittled the lead from there but still trailed 78-70 with 1:44 to go.
The Wildcats finished regulation on a 10-2 run, helped by two missed free throws by Colorado's Jeremy Adams with 18 seconds to play. Lyons tied the game with two foul shots with 9.2 seconds left.
Chen had a chance to tie the game with 1:28 left in overtime, but he missed two free throws. Lyons converted a three-point play on the other end to give Arizona an 88-83 lead with 1:09 to go, and the Buffaloes would get no closer.
Senior guard Kevin Parrom helped fuel Arizona's comeback with 16 points and eight rebounds off the bench.
Sophomore guard Askia Booker scored 18 points to lead five Colorado players in double figures. Chen, a senior guard, scored a career-high 15.
Colorado was hot from the start, hitting five of its first six shots from the field and pulling away from Arizona for much of the first half. The Buffaloes led 34-27 at the break.
Colorado freshman forward Xavier Johnson, who entered with an average of 6.3 points per game, had a team-high 12 points at the break, having made all four of his shots from the field. Booker added 11 first-half points for the Buffs.
The Wildcats were cold in their first game since Christmas Day in Honolulu. They made only two of their first 15 shots and finished the half 7-for-27 (25.9 percent) from the field.
Colorado's biggest lead of the half came at 30-13 with 4:37 to go when Andre Roberson hit a 3-pointer as the shot clock expired. Arizona climbed back into contention by finishing the half on a 14-4 run, initially fueled by 3-pointers from Parrom and Grant Jerrett.
NOTES: The Colorado game marked Arizona's second sellout of the season at McKale Center. The other was for the game against then-fifth-ranked Florida on Dec. 5. ... The Buffs defeated Arizona in two of three games last season in their Pac-12 debut, including a 53-51 victory in the conference tournament championship game. ... The Wildcats hadn't opened conference play at home since the 2007-08 season. They entered Thursday night's game 12-0 in league openers since joining the Pac-10 for the 1978-79 season. ... The last time Colorado defeated a top-10 team on the road was Jan. 15, 1973, when it beat No. 5 Missouri 81-79 in overtime.