Tsohonis also hit four of Washington’s 12 3-pointers, needing every bit of the outside shooting to counter being dominated on the interior by the Buffaloes.
Jamal Bey scored 14 points and Quade Green added 11 for the Huskies.
Jeriah Horne scored a season-high 24 for Colorado, but missed an open 3-pointer with seven seconds left that could have tied the game. Colorado (11-4, 5-3) saw its four-game win streak snapped and likely lost a chance to move into The AP Top 25 next week.
Evan Battey added 18 points, but leading scorer McKinley Wright IV was held to 12 points.