The sophomore scored 24 points, tied a career high with 11 rebounds, and had six steals and five assists with no turnovers in the Cowboys' 87-74 win over the Longhorns on Wednesday night.
''I thought he gave an incredible, Marcus Smart performance tonight,'' Oklahoma State coach Travis Ford said. ''You look at the stat line - it's ridiculous.''
Markel Brown scored 27 points and Phil Forte added 14 points for the Cowboys (13-2, 1-1 Big 12), who shot 54 percent from the field in the second half after struggling early. Oklahoma State, which entered averaging 86 points, eventually overwhelmed the Longhorns.
And then, there was the free-throw difference. Oklahoma State shot 51 to Texas' 23. The Cowboys only made 35 of them, but that was enough.
''Fifty-one free throws is hard to overcome,'' Texas coach Rick Barnes said.
With Oklahoma State coaching great Eddie Sutton in attendance, the Cowboys bounced back from Saturday's loss at Kansas State.
Demarcus Holland had 12 points and 10 rebounds and Damarcus Croaker scored 12 points for the Longhorns (11-4, 0-2).
Oklahoma State had a tough challenge against a big Texas team, especially because Michael Cobbins, a 6-foot-8, 230-pound junior, is out for the season with a ruptured left Achilles' tendon.
''We knew their big guys coming in here would cause us a little bit of trouble, but we collectively gave an effort together as a team,'' Smart said. ''We pulled together and got the understanding that we were going to have to play like we had him [Cobbins] on the court, even though he wasn't there.''
Oklahoma State led by a point at halftime but raced out of the gate after the break. Back-to-back alley-oop dunks by Smart and Kamari Murphy highlighted a run that gave the Cowboys a 57-45 lead.
Oklahoma State switched to a zone defense to start the second half, a move that Ford said worked better than expected.
''I thought the zone was very good for us to start the second half,'' Ford said. ''Defensively, I thought we did a good job on a team that really pushes the basketball.''
Smart took a hit in the face, and Texas was called for a flagrant 1. Smart made both free throws, and the Cowboys remained in control from there.
The Cowboys got off to a quick start, but Texas used strong play on the offensive boards to tie the score at 20 with eight minutes left in the first half.
Croaker's 3-pointer gave the Longhorns a 27-22 lead and made the home crowd uneasy. Texas' lead swelled to eight in the first half before Oklahoma State rallied. Forte's 3-pointer trimmed the Longhorns' lead to three.
Smart scored in close, then the Cowboys regained the lead on a 3-pointer by Stevie Clark with 31 seconds left in the half. Oklahoma State led 38-37 at the break, despite shooting 39 percent and missing nine of 24 free throws.
The combination of Oklahoma State's hot shooting and continual trips to the free-throw line in the second half were too much for the Longhorns to overcome.
''We played about as bad as we could play, and we still had a chance,'' Barnes said.