"I felt like all my shots were there in the first half," Brown said. "The guys told me to keep shooting and they found me when I was open. I just had to keep confidence in myself because they were playing zone and the only way to get them out of a zone is to make shots. I think I did that, and the rest of the team did as well."
Austin Dufault added 17 for the Buffaloes (11-4, 3-0), who finished up a monthlong, eight-game home stand.
Reggie Moore scored 14 points and Faisal Aden had 12 for Washington State (9-7, 1-3), which has lost three of four.
Carlon Brown had 18 points in the second half and hit a career-high six 3-pointers. His three-point play gave Colorado a 50-31 lead. Askia Booker followed with a layup and Andre Roberson hit a 3-pointer to give the Buffaloes a 55-33 edge with 11:21 left.
The Cougars went on an 11-1 run to pull within 65-57 with 2:42 left, but Colorado hit 6 of 8 free throws down the stretch to secure the win.
"I'm proud of our guys for coming together, believing and improving," CU coach Tad Boyle said.
-- BuffaloSportsNews staff contributed to this report