Que Johnson led the Cougars with 14 points, fellow guard Kernich-Drew added 11 points and forward D.J. Shelton pulled down a team-high eight rebounds.
In the 5-minute overtime period, Colorado (14-2, 3-0) went on a 10-4 run to take command of the game. Despite a couple late threes that brought the Cougars to within one, Washington State suffered its third straight conference loss to open the Pac-12 season.
Mike Ladd finished with 14 points and has now scored in double figures in each of the last nine games, but the rest of the squad had a tough time containing the Arizona State offense.