Colorado put an end to No. 2 Arizona's nine-game winning streak on Saturday with a 79-63 upset that marks just the second conference loss of the season for the Wildcats (25-3, 15-2 Pac-12). It's the first loss outside of Quad 1 this season for Arizona, a projected No. 1 seed in the NCAA Tournament entering the day, and will remain on the top line, CBS Sports Bracketology expert Jerry Palm said before overall No. 1 seed Gonzaga's game vs. Saint Mary's finished Saturday night. 

Tristan da Silva led Colorado with 19 points, including a dagger 3-pointer with 2:01 remaining that put the Buffs (19-10, 11-8) ahead 75-59. He was one of five players in double figures for a Colorado team that just lost by 17 at home against Arizona State on Thursday. Until that loss, the Buffs had won five straight, and they picked the right moment to recapture that winning form.

With a win over Colorado and an Oregon win over USC on Saturday night, Arizona would have clinched an outright Pac-12 title. Instead, the Wildcats will have to wait until next week, when they play USC, Stanford and California to close the regular season.

Arizona led 37-32 at halftime behind a 12-point half from Bennedict Mathurin. But the Wildcats' dynamic wing did not score in the second half and attempted just three shots as the Buffs began to heat up. Colorado outscored Arizona 31-13 over the first 13 minutes of the second half before the Wildcats finally staged a rally. Arizona drew within six at the 5:28 mark before another Colorado run sealed the deal.

The Buffs are not considered an NCAA Tournament bubble team and will likely need a run through the Pac-12 Tournament to reach the Big Dance. But the win guaranteed the program its fourth straight winning season in Pac-12 play and gave its fans a reason to let loose. Just seconds after the buzzer sounded, students poured onto the floor in celebration.