Washington State lost the lead, scrapped to force overtime, and ultimately defeated Colorado on senior day, 96-91.
With the loss, Colorado locks up the 10-seed in next week's Pac-12 tournament. The Buffs will face the seventh seed Oregon State on Wednesday night. The winner will earn the chance to play Oregon, who clinched the two-seed with a strong late-season push.
Colorado shot 50 percent from the field in the first half, but allowed the Cougars to shoot an astronomical 60.6 percent. Washington State hit 13 consecutive field goals at one point, spanning a stretch of over ten minutes.
Washington State's lead bounced between six and 10 points for most of the season half. Jaron Hopkins hit a leaner along the left baseline to cut the deficit to 67-63 with 8:20 to play. Askia Booker was able to get the Buffs within two, 67-65 on the following possession. Back-to-back buckets by Josh Scott and Xavier Johnson cut the WSU lead to just one.
Booker gave CU their first lead of the second half with a transition layup with 4:32 to play. Josh Hawkinson knotted the contest at 73 with a free throw, and Gordon was called for goaltending on a Jordan Railey hook shot, giving the Cougars the lead back, 75-73.
Booker slipped two defenders and drove to the basket to tie the score at 75 with 1:08 left to play. Wesley Gordon came up with a huge block and defensive rebound with 47 seconds left. Tad Boyle called timeout, and drew up a play for Scott, who knocked down a jumper to give CU the 77-75 lead.
Ike Iroegbu threw up a wild runner and caught the rebound out of bounds, giving the Buffs the ball with 10 seconds to go. CU inbounded to Booker in the right corner, who was immediately trapped and tied up, with the possession arrow favoring WSU. Davonte Lacy hit a free throw line jumper with 1.1 seconds left to send the game into overtime.
Washington State scored the first six points of the extra session, with threes Dexter Kernich-Drew and Lacy. Xavier Talton was able to cut the Cougars' lead to 85-83 with 1:34 to play with a steal and layup. Kernich-Drew responded by hitting a jumper in Johnson's face, putting the WSU lead back at four.
The Cougars hit their free throws, and Colorado never got closer than three in the final minute.
Scott had another terrific game, pouring in a career-high 32 points and grabbing 12 boards. Booker added 26 points, but finished 0-of-7 from downtown.
Colorado finishes the regular season 14-16 (7-11).