AMES, Iowa (AP) _ Justus Thigpen scored 11 of his 22 points in overtime, then set up Fred Hoiberg for the game-winning three-point play with 8.9 seconds left as Iowa State handed No. 2 Oklahoma State its second straight loss, 84-83 on Saturday.

Iowa State (18-6 overall, 4-4 Big Eight), shooting 80 percent after halftime, rallied from an 18-point deficit in regulation and a seven-point deficit in the overtime.

Darwyn Alexander had a chance to pull it out for Oklahoma State (21-3, 5-3), which lost at Colorado on Wednesday night, but missed two free throws with 2.4 seconds left.

Thigpen, who had only four points at halftime, scored on a drive with 10 seconds left in regulation to tie the score at 67. He then rescued the Cyclones after they fell behind 75-68 in the overtime.

Thigpen hit a jump shot and three straight 3-pointers to pull Iowa State to 82-81 with 37 seconds left. Oklahoma State's Milton Brown then sank one of two free throws to make it 83-81 and it looked as if Iowa State would go to Thigpen one more time.

But he faked the shot and passed to Hoiberg cutting to the basket. Hoiberg was fouled by Corey Williams and made the free throw.

Oklahoma State's Cornell Hatcher got the rebound after Alexander missed his second free throw and passed to Bryant Reeves. But the 7-foot freshman couldn't hold the ball and time expired.

Ron Bayless scored 22 points for Iowa State, which won its 15th straight home game, and Hoiberg finished with 18 - 14 in the second half.

Byron Houston led Oklahoma State with 21 points and Sean Sutton added 17.

Oklahoma State shot 63 percent in building a 38-20 halftime lead and led 45-27 after Williams' three-point play with 16:39 remaining. But the Cowboys went scoreless over the next 5 1/2 minutes and Iowa State got back in it.

Hoiberg's layup capped a 12-0 run that cut the lead to 45-39 with 12:38 left. Oklahoma appeared to have some breathing room after Sutton's layup gave the Cowboys a 55-45 lead with 7:21 remaining, but they made only one more field goal in regulation and Iowa State stormed back.

Bayless' two free throws left Iowa State trailing 66-62 and Thigpen made a 3-pointer to cut the lead to 67-65 with 43 seconds left. Teammate Julius Michalik then intercepted Hatcher's cross-court pass and fed Thigpen, whose driving layup tied the score.

Hatcher's 24-foot shot bounced off the front of the rim at the buzzer.

The first half was all Oklahoma State. With Iowa State opening in a zone, six of Oklahoma State's first seven baskets were 3-pointers, including two each by Sutton and Houston.

Houston's second 3-pointer gave the Cowboys a 19-11 lead and Reeves followed with a basket inside to make it 22-11. Iowa State then switched to a man-to-man and the Cowboys went inside. They ended the half with a 14-4 run that included two dunks by reserve Randy Davis and five layups.