Brittany Boyd recorded 15 points, eight rebounds and six assists as No. 7 California outlasted 20th-ranked Colorado, 53-49, at Coors Events Center.
Reshanda Gray and Afure Jemerigbe followed with 10 points, while Gennifer Brandon pulled down a game-high 11 rebounds for the Golden Bears (12-1, 2-0 Pac-12), who have won six straight.
Chucky Jeffery paced the Buffaloes (11-2, 0-2) with 13 points and eight rebounds.
Arielle Roberson added 11 points and six rebounds as Colorado dropped its second straight game after opening the season with 11 consecutive wins.
The game entered the break tied at 24-24 after a back-and-forth opening 20 minutes that saw neither team take a lead larger than four points and the teams continued to trade blows in the second half.
California, however, was finally able to take control of the game when the Golden Bears followed Roberson's three-point play that tied the game at 38-38 with an 8-0 push to go on top for good.
The Buffaloes answered with a Jen Reese jumper followed by a Roberson 3- pointer to cut their deficit to 46-43 with 4:45 to play, but California scored the game's next five points to regain an eight-point lead.
Back-to-back layups by Jeffery and a Brittany Wilson jumper brought Colorado back within 51-49 with 23 seconds to play, but the Buffaloes would not see the ball again as Gray grabbed the offensive rebound after Layshia Clarendon missed a pair of free throws at the other end to seal the win for the Golden Bears.