McKinley Wright IV scored 18 points and Colorado held off California 56-51 on Wednesday in the opening round of the Pac-12 tournament.
The fifth-seeded Buffaloes (20-11) had a hard time holding onto the ball, committing a season-high 23 turnovers, but made up for it by shutting down the Bears defensively.
Colorado used an eight-point burst midway through the second half to go up 10 and held off a late Cal charge to remain undefeated (8-0) in Pac-12 Tournament first-round games
The Buffaloes move on to face No. 4 seed Oregon State in Thursday's quarterfinals.
The 12th-seeded Bears (8-23) shot nearly 50 percent while winning their final three regular-season games, but reverted to their shooting struggles in the Pac-12 Tournament.
Cal trimmed a 10-point lead to three in the final minute and had a shot to tie after a 3-pointer by Wright was waved off upon review. Matt Bradley got a decent look at a 3-pointer, but his shot hit front rim and Colorado's Tyler Bey hit two free throws with 2.4 second left to seal it.
Bradley had 17 points to lead the Bears, who shot 34 percent.
Cal lost its first 15 Pac-12 games before stunning eventual champion Washington on Feb. 28. The Bears followed with wins over Washington State and rival Stanford to close out the regular season and head into the Pac-12 tournament on a mini roll.
The Buffaloes landed in Las Vegas on a bit of roll as well, winning eight of their final 10 games to just miss an opening-round bye as a top-four seed.
Colorado won the lone regular-season meeting 68-59 after blowing an 18-point lead.
The rematch was a defensive battle early, with neither team able to get into much of a rhythm.
The Buffaloes triggered a 13-2 run with their defense, going up 23-14 after a pair of steals and break-away dunks by Daylen Kountz.
Cal shot 8 for 25 in the first half, but was within 28-22 at halftime thanks in part to forcing 12 Colorado turnovers.
The Bears continued to speed up the Buffaloes to start the second half, getting them to turn it over four times in four minutes to pull within 32-31.
Colorado took control with a quick 8-0 spurt to go up 10, but went more than three minutes without scoring as Cal cut the lead to 50-47.
The Bears were able to keep Colorado within reach, but couldn't come up with the big plays when they needed them.
Colorado played just well enough to win, but will need to clean up the turnovers if it's going to advance again in the Pac-12 tournament.
Cal's late-season offense resurgence ended in Las Vegas and so did its disappointing season.
Colorado faces Oregon State in the Pac-12 quarterfinals.
Cal's season is over.