STILLWATER, Okla. (AP) -- Alison Lacey scored 15 points and Heather Ezell added 12, including the go-ahead free throws with 41.1 seconds left, as Iowa State sustained a second-half rally by No. 15 Oklahoma State and beat the Cowgirls 62-57 on Sunday.
After trailing by 13 early in the second half, Oklahoma State clamped down on the Cyclones' perimeter shooting to mount a comeback.
The Cowgirls (20-4, 8-3 Big 12) pulled ahead with a run of seven straight points that Maria Cordero capped with a fast-break layup to put Oklahoma State ahead 54-52 with 2:08 remaining.
Lacey cut the deficit in half with a free throw, and Ezell -- who was fouled on the Cyclones' second straight offensive rebound -- hit two foul shots to put Iowa State ahead 55-54.
Andrea Riley, the Big 12's leading scorer, missed a layup on Oklahoma State's next possession and then flopped after heaving a long 3-pointer from the edge of the midcourt logo following two more free throws by freshman Kelsey Bolte.
Lacey added two free throws to stretch the lead to 59-54 before Riley sank a long 3 from the right wing to give Oklahoma State one last chance.
Iowa State (16-8, 5-6) was able to inbound the ball to Lacey, who was fouled and hit one free throw with 3.3 seconds left, and 5-foot-8 guard Denae Stuckey put back the second foul shot.
Bolte finished with 12 points and Amanda Nisleit hit a career-high three 3-pointers and scored all 11 of her points in the first half for Iowa State, which improved to 1-4 in games decided by five points or less this season. It was the second time the Cyclones have upset a Top 25 team on the road this year.
Riley led Oklahoma State with 18 points, Shaunte Smith scored 16, Cordero had 13 and Danielle Green added 10. The Cowgirls had a four-game winning streak stopped.
Iowa State quickly broke down Oklahoma State's zone, with Lacey and Ezell nailing 3-pointers during an 8-0 start by the Cyclones. The Cowgirls switched up defenses and got back in the game with a run of seven straight points of their own, but then Iowa State got hot again.
Bolte, Nisleit and Lacey combined to sink five straight 3-pointers during a 15-4 surge by the Cyclones that extended their lead to 30-16.
After starting out 9-for-15 from beyond the arc, the Cyclones missed their next eight 3-pointers as Oklahoma State started its comeback.
Riley and Smith combined to score nine straight points, and the Cowgirls got within 38-34 on Riley's steal for a fast-break layup with 15:15 remaining.
Ezell finally broke Iowa State's 3-point drought from the top of the key for a 52-47 lead with 5:59 left, but the Cyclones went more than 5 minutes without scoring to allow Oklahoma State to take its first lead.