STILLWATER, Okla. -- Students rushed onto the floor, jumping up and down and hoisting Keiton Page as they celebrated a historic win for Oklahoma State.
The bottom line for the Cowboys: "We're a tournament team now," forward Obi Muonelo said.
James Anderson scored 27 points, 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 Cowboys (20-8, 8-6) moved to 3-1 against top-ranked teams all time at home and likely removed any doubt of whether they would make the NCAA tournament for a second straight season. Despite entering the game in seventh place in the Big 12, OSU 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.
Teammate Fred Gulley headed toward the safety of the scorer's table as fans spilled out of the student sections along both baselines. But Page was right in the middle of it all.
"That was a great feeling," Page said. "I was claustrophobic. I was getting hot, so when they picked me up, I got a little breather. I was pretty excited when they did that. I thought I was going to pass out there for a little while."
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.
Sherron Collins had 22 points to lead Kansas -- moving past Kirk Hinrich, Dave Robisch and Paul Pierce into seventh place on the school's career scoring list -- but he also matched his season-high with six turnovers. Freshman Xavier Henry added 17 points and Cole Aldrich scored 11 but had little impact on the boards with only five rebounds.
The Jayhawks, who had held 101 of their previous 102 opponents below 50 percent from the field, allowed Oklahoma State to shoot 60 percent and make 10 of 19 from 3-point range.
"Obviously we weren't good offensively today by any means. We couldn't make a basket when they got their lead," coach Bill Self said. "So in those times, that's when you've got to guard. And obviously our toughness level defensively today was very, very poor and that can happen in the tournament in a one-and-done deal again.
"Hopefully we can learn from that and understand that we weren't ready to defend today."
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.
"Our guys just played extremely hard," OSU coach Travis Ford said. "I told our team, 'You played against a team today that has a great, great chance to win national championship.' I would pick them to win the national championship is what I would do. Today just happened to be our day."
Oklahoma State got a scare when Anderson, the nation's sixth-leading scorer and the Big 12 leader with 22.5 points per game, left practice with back pain. It wasn't much better when he arrived at the arena, and he skipped the pregame shootaround.
"I was going to play regardless," Anderson said. "I could have been with a broken leg. I was going to drag it all the way down the court."
Matt Pilgrim made all eight of his shots had 18 points after missing OSU's last game due to a suspension, 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.
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.
"The last time we came down here and left here sad, it turned out OK," Self said. "So, I'm believing that we can get something out of it. But I don't think that the thing is broken but I do think we need to really evaluate our things that we must take pride in to be a good team - especially this time of year."
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 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.
Anderson and Page hit consecutive 3s again -- with Aldrich and Collins on the bench again -- to put the Cowboys up by 12 and the lead grew to 45-26 on Marshall Moses' left-handed dunk with 1:02 left before halftime.