It was Washington's first win over a ranked team since Isaiah Thomas' jumper beat then-No. 16 Arizona in the 2011 Pac-10 Conference tournament championship game. Washington (11-6, 3-1 Pac-12) had lost 12 straight against ranked teams.
Colorado (14-3, 3-1) never recovered after leading scorer Spencer Dinwiddie crumbled to the court late in the first half after his left knee buckled while dribbling on a fast break. Dinwiddie had to be helped to the locker room by teammates and did not return.
The Huskies outscored the Buffaloes 49-29 after Dinwiddie's injury.
Josh Scott led Colorado with 14 points, but the Buffaloes' struggles went beyond just not having Dinwiddie around in the second half.
Askia Booker, the reigning Pac-12 player of the week, was 0 for 9 from the field and went scoreless for just the second time in his college career. The last time Booker failed to score was late in his freshman season against Arizona.
Colorado was trying for the second-best start in school history, but fell short after being pushed to overtime by Washington State on Wednesday night in Spokane.
Dinwiddie crumpled to the court after taking an awkward step on a fast break and his left knee buckled. He was on the court for a few minutes while trainers and coach Tad Boyle came on to his side. Dinwiddie was helped to his feet but had to be assisted off the court with his arms around teammates.
Dinwiddie, who had seven points in 15 minutes, was chastised by Boyle after scoring a disappointing six points in 38 minutes on Wednesday night.
Less than 90 seconds later Colorado's Tre'Shaun Fletcher limped off the court holding his left knee after colliding with Perris Blackwell of the Huskies. Fletcher returned in the second half.
Wesley Gordon did his part to pick up for Dinwiddie's absence. He had nine points and 11 rebounds in the first half, including Colorado's final four points of the half as the Buffs led 29-26 at the break. Gordon had just two points in the second half.
Andrew Andrews added 14 points for Washington and Nigel Williams-Goss had 12.
The Buffaloes had no answer for Wilcox's shooting in the final 20 minutes. Washington started the second half on a 12-5 run thanks to three 3-pointers from Wilcox. The complexion of the second half could have changed when Blackwell, the Huskies' only true inside presence, picked up his fourth foul with 15:52 remaining. Scott tried to stem the run with five straight points for the Buffaloes but Wilcox continued to knock down shots. He hit another 3 when Williams-Goss broke the Colorado press and found him open in front of the Washington bench. He scored off a steal with a left-handed layup and hit another stand-still 3 for a 51-39 lead, his sixth straight make to start the second half.
Andrews added a driving layup to push the lead to 14 before Scott finally scored in the lane to briefly stop the run. Washington went up 18 when Wilcox knocked down his seventh 3-pointer with 6:42 left for a 61-43 lead.