STILLWATER, Okla. (AP) - James Anderson scored 27 points, Keiton Page was perfect on four 3-point tries at crucial times and Oklahoma State denied a bid by No. 1 Kansas to go undefeated through Big 12 play with an 85-77 victory on Saturday.
The Jayhawks (27-2, 13-1) had won their last 13 games since losing at Tennessee to close nonconference play and suffered their second loss of the season just hours after No. 2 Kentucky also lost to the Volunteers.
The last time the top two teams lost on the same day was Jan. 21, 2006, when No. 1 Duke lost to Georgetown and No. 2 Florida lost to Tennessee. Both of those teams were 17-0 at the time.
Students stormed the court after Oklahoma State (20-8, 8-6) moved to 3-1 against top-ranked teams all-time at home and likely removed any doubt of whether it would make the NCAA tournament for a second straight season. Despite entering the game in seventh place in the Big 12, the Cowboys had an RPI of 33.
It was OSU's first win against a No. 1 team since beating Oklahoma on Feb. 4, 1989, and the landmark victory came in the same season the program got its first road win over a top 10 team in 52 years.
Sherron Collins had 22 points to lead Kansas, which allowed Oklahoma State to shoot 60 percent from the field and make 10 of 19 from 3-point range. Freshman Xavier Henry added 17 points and Cole Aldrich scored 11 but had little impact on the boards with only five rebounds.
The Cowboys used strong 3-point shooting to build a 19-point lead late in the first half and then held off a late charge by Kansas fueled by its full-court press. The Jayhawks closed within 80-74 on Henry's 3-pointer with 1:08 remaining but Anderson hit three of four free throws on the Cowboys' next two possessions and swatted Tyshawn Taylor's shot in between.
The only thing that stopped the celebration after that was a malfunction that stopped the clock as it ran down - fittingly with all ones at 11.1.
Matt Pilgrim had 18 points after missing OSU's last game due to a suspension, Obi Muonelo scored 17 and Page was 4-for-4 from 3-point range on his way to 15 points. Oklahoma State was 32-for-53 from the field and became only the second of Kansas' past 103 opponents to shoot over 50 percent.
Page hit 3-pointers on consecutive possessions to keep the Jayhawks at bay after they had closed within 63-50 as Anderson rested on the bench midway through the second half. That proved to be a big enough margin for the Cowboys to protect despite difficulties against pressure down the stretch.
OSU beat Kansas for the fourth time in six games at Gallagher-Iba Arena, including its last visit in 2008. That proved to be the Jayhawks' last loss on their way to the national championship.
Kansas hadn't trailed by more than 11 all season and led from start to finish in each of its previous two games.
The Cowboys capitalized on a brief, 42-second period when Kansas put both Collins and Aldrich on the bench to create an early spark. Anderson and Page hit back-to-back 3-pointers before Bill Self called timeout and put Collins back in, but OSU was already on its way to a 16-2 run. Pilgrim's jumper put Oklahoma State up 23-12, and the Cowboys wouldn't trail again.
Kansas scored the next five points before a lengthy replay determined Marcus Morris wasn't behind the arc for what had been ruled a 3-pointer, and Anderson and Page hit consecutive 3s again - with Aldrich and Collins on the bench again - to put the Cowboys up by 12.
Anderson curled into the lane for a layup and then hit a 3-pointer to make it 36-20, causing Self to call on seldom-used reserve Jeff Withey to find a spark. The Cowboys added to their lead, though, with Anderson making a baseline jumper and then setting up Marshall Moses for a left-handed dunk that made it 45-26 with 1:02 left before halftime.
Collins made a 3-pointer to get the Jayhawks within 16 at intermission but OSU restored its lead early in the second half.