Kaylee Jensen had 24 points and 11 rebounds to help No. 25 Oklahoma State defeat No. 20 Oklahoma 71-69 on Wednesday night.
It was Oklahoma State's first win in Norman since 1998 and the Cowgirls' first regular-season sweep against the Sooners since that year.
Brittney Martin had 18 points and 10 rebounds for the Cowgirls (17-4, 7-3 Big 12), who won their fifth straight.
Oklahoma State shot 49 percent overall and 50 percent from 3-point range. The Cowgirls made 5 of 7 3-pointers in the second half after almost exclusively pounding the ball inside early.
The Cowgirls broke a tie with the Sooners and moved into sole possession of third place in the conference.
Gioya Carter scored a season-high 17 points, and Maddie Manning and Peyton Little both added 12 for the Sooners (15-6, 6-4), who had won two straight.
Oklahoma State won the previous meeting 73-42 in Stillwater.
Jensen made a 3-pointer, just her fourth of the season, to put Oklahoma State up 68-65 with 1:04 to play.
Oklahoma's Gabby Ortiz made a pair of free throws, then Carter knocked down a mid-range jumper with 27 seconds remaining to put the Sooners ahead 69-68.
Martin drove and scored with 12.4 seconds to play, putting the Cowgirls up 70-69.
Oklahoma's Kaylon Williams missed in close and Jensen rebounded and was fouled with 2.8 seconds remaining. She made the first free throw and missed the second, and Little's heave from near half court just missed.
Oklahoma jumped out to a 16-7 lead on the strength of seven early points by Carter. The Cowgirls rallied behind Jensen and trimmed Oklahoma's lead to 39-35 at halftime. Jensen had 16 points in the first half on 7-for-8 shooting to keep the Cowgirls in it.
The Cowgirls took the lead for the first time on a 3-pointer by LaTashia Jones with just under nine minutes remaining in the fourth quarter, and the game was close the rest of the way.
Oklahoma State: Shot 56 percent in the first half. ... Martin became the fourth Oklahoma State player ever to record at least 1,000 points and 1,000 rebounds in a career.
Oklahoma: Former Oklahoma and current WNBA star Danielle Robinson attended the game. ... Oklahoma made just 4 of 17 3-pointers.
Oklahoma St. hosts Texas Tech on Sunday.
Oklahoma hosts TCU on Saturday.