That's when all the trouble started.
Suddenly incensed, Smart got in the face of a Texas Tech fan who appeared to say something to the star guard. Smart shoved him with two hands.
The man stumbled backward a bit, but didn't fall. Teammates quickly pulled Smart away from the fracas, and he pointed back in the direction of the fan.
Smart was called for a technical foul but was not ejected. He remained on the bench until the final buzzer.
As fans stormed the court to celebrate Texas Tech's 65-61 win Saturday night, Smart was escorted off the floor by a man wearing Oklahoma State colors - with a uniformed police officer trailing right behind.
A unanimous selection to the preseason All-America team, Smart could now face discipline from the Big 12. Texas Tech spokesman Trenten Hilburn said John Underwood, the conference's associate commissioner for basketball, said the league would review the situation.
"I didn't see it yet. I want to make sure I see it and see what happened," Oklahoma State coach Travis Ford said after the game. "I'm still trying to figure it out."
No Cowboys players were made available to reporters after the game.
Smart tried to block Jaye Crockett's dunk attempt from behind with 6.2 seconds to go and tumbled into the front row of the crowd.
He was helped up by one man but then went after another, Jeff Orr, who travels thousands of miles each year to attend Texas Tech basketball games, according to athletic department spokesman Blayne Beal.
Smart pushed Orr, and fans nearby looked stunned - one wide-eyed woman next to Orr pointed at Smart as he was pulled away.
Texas Tech coach Tubby Smith said he turned away from the play and didn't see the altercation.
"You really have to find the film to see what happened," he said. "I assume the officials saw what happened. That's why he got a technical out of it. The frustration when you're losing sometimes on a losing streak, I've been there before, it can be tough. I'm sure he regrets doing that, whatever he did, so things like that happen in the heat of the battle."
Crockett scored 21 points and tied his season high with 12 rebounds to lead Texas Tech.
Smart had 22 points and Phil Forte added 15 for the Cowboys (16-7, 4-6 Big 12).
Considered one of the best all-around players in the country, Smart has showed frustration more than once during an inconsistent season.
The sophomore guard got off to a fantastic start, leading to speculation that he could be the No. 1 pick in the NBA draft this year. He has struggled in some recent games, though, including a four-point effort against West Virginia when he kicked a chair on the bench. That led to him apologizing to his teammates afterward.
This one was tied at 61 when Crockett hit the go-ahead shot with 41 seconds remaining. Oklahoma State's Le'Bryan Nash lost the ball in the lane, and Crockett raced toward the basket at the other end.
Smart knocked the ball away and was called for a foul, then pushed Orr and drew the technical. Dusty Hannahs and Crockett each made one of two free throws for the final margin.
The Red Raiders (12-11, 4-6) earned their second win over a Top 25 team in the past month. They beat then-No. 12 Baylor in January.
None of Texas Tech's players had ever played in front of a sellout crowd at home before. The last two at United Spirit Arena came in January 2007, including New Year's Day when former Red Raiders coach Bob Knight got his 880th win to become the winningest coach in Division I.
This victory gave the Red Raiders as many Big 12 wins this season as they had the past two years combined.
The score was tied 13 times and the lead changed 12 times as each team put together runs throughout the game.
Oklahoma State went on a 17-7 spurt to open the second half, including two 3-pointers by Forte and six points from Smart, to go up 44-36. But the Red Raiders didn't buckle. They used a 9-2 run to pull to 46-45 with 11:14 remaining.
Texas Tech went ahead 51-48 on a 3 by Crockett right before Kamari Murphy picked up his fourth foul with 7:47 left. The Cowboys answered, culminating with a 3-pointer from Smart to go up 57-54 with 4:31 remaining. Crockett quickly tied it at 57 with a 3.
Oklahoma State struggled early, making one field goal in 11 tries. But the Cowboys used a 10-0 run to go up 14-10.
The Red Raiders answered with a 9-2 run and later an 8-2 spurt in the final 1:29 of the half to lead 29-27. Oklahoma State's point total for the half was a season low.