The Buffs were leading by four points with just over seven minutes remaining in the game when Shane Harris-Tunks decided to seize the moment.
Colorado's 6-11 center went up strong with the ball and missed a dunk that would have sent the capacity crowd of 11,056 into a frenzy.
Arizona scored the next four points and tied the score 56-56 before Austin Dufault and Carlon Brown made enough plays to recapture the momentum and help CU hold on for a 64-63 victory over the Wildcats on Saturday at the Coors Events Center.
CU fans might be wondering about Harris-Tunks' confidence right now. The redshirt sophomore also missed a point-blank chance late in the first half.
But Harris-Tunks' overall performance -- he finished with five rebounds, four points and an assist in 15 minutes -- was an encouraging development for the Buffs.
"I was feeling pretty good. I didn't quite get my dunk, but the fact that I felt like I could go for it is a confidence booster for me," Harris-Tunks said. "I'm getting to that point again where I'll actually think about dunking the ball because my legs feel like I can do it.
"I think that's a big step psychologically for me, even though I didn't finish it."
Harris-Tunks suffered a torn anterior cruciate ligament in his left knee 15 months ago and missed the entire 2010-11 season.
Second-year CU head coach Tad Boyle can only wonder how good the 24-win
Through 19 games, Harris-Tunks is averaging 3.0 points and 2.5 rebounds off the bench.
"Anytime you miss an entire year, mentally I think it's tough coming off an injury like the one Shane had," Dufault said after finishing with 12 points and six rebounds against Arizona.
CU needed Harris-Tunks contributions on Saturday as forward Andre Roberson got into early foul trouble and did not score after missing all eight shots he took.
Freshman forward Damiene Cain, a player Boyle believed would have a major impact in the post, left the program last week.
The Buffs will face two teams this week in Los Angeles that have a lot of size down low.
USC's starting center, Dewayne Dedmon, is listed at 7-foot and 255 pounds. UCLA's front line includes 6-10 twin forwards Davis and Travis Wear and 6-10, 305-pound center Joshua Smith.
"Both teams have some pretty good big guys. I'm probably our biggest big guy and will have to bang more with those guys," Harris-Tunks said. "I really have to focus on controlling that and staying in the game."
Harris-Tunks is confident that he will convert his scoring chances with more consistency as the season wears on. He understands his role on the team begins on the defensive end.
"I try to concentrate a lot on my defense and I think I helped clog up the paint well (against Arizona)," Harris-Tunks said. "A big thing for us is our defense and that's definitely what won us this game. Our offense really wasn't flowing as well as it usually it is. We really hunkered down on defense and grinded it out."