STILLWATER — Marcus Smart scored 21 points and hit the winning layup with 3.1 seconds left to lift Oklahoma State to a 78-76 victory against Iowa State on Wednesday night.
Smart zipped back and forth beyond the free throw line trying to lose Iowa State's Will Clyburn before knifing into the lane and releasing a runner over Georges Niang that banked off the glass and in for the Cowboys (14-5, 4-3 Big 12).
Tyrus McGee missed a desperation 3-pointer at the buzzer for the Cyclones (14-6, 4-3), who had two chances in a wild final few seconds. For a moment, it appeared Chris Babb would have a chance at two free throws to tie it up with less than a second left before officials huddled and ruled that Iowa State should instead get the ball out of bounds.
Babb ended up with a season-high 19 points to lead Iowa State.
Babb stepped to the free-throw line and was ready to shoot a one-and-one before John Higgins and his crew gathered and ruled that Le'Bryan Nash's foul was an offensive foul and shouldn't result in free throws. Babb got in front of Nash to catch a long inbounds pass, and Nash shoved him in the back as the ball was in the air to bring on the whistle.
Instead, Babb inbounded from near midcourt, and McGee launched a running 3-pointer that was off-target.
After Smart's decisive bucket, Nash burned the Cowboys' last foul to give, and McGee was out of bounds when he caught another inbounds pass from Babb on a similar play. Cyclones coach Fred Hoiberg argued that McGee had been forced out, to no avail.
Oklahoma State erased an 11-point deficit in the second half to turn it into a nail-biter, with 10 lead changes over a 6-minute stretch before Melvin Ejim's layup made it 71-70 Iowa State with 4:25 remaining. McGee followed with a 3-pointer, and the Cyclones were up 76-72 after Korie Lucious' driving layup with 2:16 to play.
The Cowboys scored the next four points from the foul line to tie it, then got a chance to go ahead after Clyburn's drive against Nash came up empty with 30 seconds left.
Niang added 16 points and Clyburn scored 14 for Iowa State, which lost for the 18th straight time at Gallagher-Iba Arena. The Cyclones haven't won in Stillwater since 1988.
Nash chipped in 18 points for Oklahoma State and Phil Forte had 17, including three free throws in the final 2 minutes — two of them after Ejim blocked his shot and then slammed into him on the way back down.
The Cyclones shot 59 percent in the first half and outrebounded Oklahoma State 19-11, but never could shake free. Nash and Smart combined for 27 points in the first half, and Smart connected on a half-court shot at the buzzer to bring the Cowboys to within 41-37 at halftime after they had trailed by as much as nine.
Iowa State stretched its lead to 50-39 after Melvin Ejim's hook shot in the lane with 17:19 to play. Forte sparked Oklahoma State's comeback with a pair of 3s, and the Cowboys regained the lead at 54-53 when Nash completed a 10-0 run with a pair of free throws with 12:10 remaining.
Brian Williams made his season debut for the Cowboys after missing the first 18 games following surgery on his left wrist.