Andre Roberson scored the game-winner with 29 seconds left, capping Colorado's game-closing 8-0 run and the Buffaloes handed No. 19 Oregon its third straight loss, 48-47 on Thursday night.
Roberson finished with 10 points and 13 rebounds for the Buffaloes (15-7, 5-5 Pac-12), who trailed 47-40 with just under 4 minutes to play.
E.J. Singler scored 14 points for the Ducks (18-5, 7-3), who had their 20-game home winning streak snapped.
Singler had a chance to win it for Oregon but his long jumper was tipped and fell into Roberson's hands with 1.1 seconds left.
The Ducks led 28-23 at halftime and never trailed until Roberson put back his own miss with 29 seconds left, a possession set up by an offensive foul by Singler, Oregon's fourth straight turnover.
Carlos Emory had 14 points for the Ducks.