The Cowboys finished the first half on a 16-4 run, and they carried a 37-22 lead into the locker room.
Marcus Smart started just 1-12 from the floor, and the Frogs used a 10-0 run over a five minute stretch to stay within six points with eight minutes to play.
However, TCU's 2-3 zone left openings on the perimeter for sophomore Phil Forte (who had 16 first half points) and Oklahoma State's other shooters, and the Cowboys finished with 14 3-pointers made as Forte finished with 23 points.
Marcus Smart played in his second game since his suspension, and he finished with five made 3-pointers, but he was most pleased that he had over 50 family members in attendance.
"It was very exciting to see my family members out there today," Smart said. "I'm a big family person. I have a big family and a lot of them were out there today. It eased my mind a little bit."
TCU's Karviar Shepherd had his second straight double-double while Kyan Anderson led the Frogs in scoring with 15.
Shepherd and Anderson joined head coach Trent Johnson in talking to the media after the loss.
On defending OSU's shooters: At the same time, I don't feel like we were closing out to the best ability that we could. With the zone, it's hit or miss for the team, and they were just on tonight.
On the OSU press: A good team is going to score off transition and turnovers, and when they started pressing us, we didn't do a good job of operating off the press.
On having limited bodies in practice: You can't really simulate game-like situations. It makes it harder for us, not having a full roster. We watch enough film to get a feel on what you have going against you.
On learning throughout his freshman year: Being out there on the court every day is a learning experience, learning how to play with Kyan, one of the best guards in the conference...I am just trying to do the simple things and help my team win...We're looking to improve every game, every day. That's all you can do and play hard.
Opening statement: We got a tired group. OK State is a really good basketball team. I thought we did everything we could possibly do as far as our zone...You have to pick your poison with that group. In the second half, we were right there within 6 or 7, and Marcus took the game over. I can't say enough about what Kyan has done...Karviar in the post, we would have liked to get him more touches...I just would have liked to been able to keep that thing close down the stretch.
On Marcus Smart: Where he hurt us was when travis put him at the 4 versus our zone, and he hurt us in the middle. He does so much that doesnt involve scoring that wins. Shame on him for having one mistake. That's a joke. Wow. The kid made one mistake. He doesn't make many.