The No. 19 Longhorns were in no mood to show them any mercy.
Javan Felix scored 27 points, making six of Texas' 11 3-pointers, and the Longhorns rolled to an easy 87-68 win Tuesday State behind a dominant first half.
Felix, who missed a game with a concussion a week ago and was just a 30 percent shooter from long range on the season, was 6 of 8 on 3-pointer and fell one point shy of his career high.
"I know I can make those shots. It's a matter of me taking them," Felix said.
Felix scored eight consecutive points that pushed Texas' lead to 22 early in the first half. The Longhorns (19-5, 8-3) had four players score in double figures and led 54-33 at halftime despite playing without leading scorer Jonathan Holmes, who sat out with a knee injury.
Smart sat out the first of a three-game suspension from the Big 12 for shoving a fan at Texas Tech on Saturday. Without him, the reeling Cowboys never had a chance.
"We're going through a tough time right now. We're not down, not blaming anybody else," Oklahoma State center Kamari Murphy said. "There's no excuses."
Le'Bryan Nash led Oklahoma State (16-8, 4-7) with 23 points.
Smart, who averages 18 points, will miss games against Oklahoma and Baylor before returning for the Cowboys' rematch with Texas Tech.
The Cowboys struggled without their star, but the Longhorns didn't miss a beat without Holmes. Isaiah Taylor scored 16, Martez Walker scored 12 and Cameron Ridley had his sixth double-double of the season for Texas with 12 points and 13 rebounds.
Texas' outburst came three days after the Longhorns scored just 18 points in the first half of a loss at Kansas State that ended a seven-game winning streak. Back home, Texas made eight 3-pointers and shot better than 50 percent for most of the first half.
Conner Lammert, who got just his second start of the season in place of Holmes, made three 3-pointers in the first half. Felix turned it into a rout when he made two 3-pointer and a layup in a burst that pushed Texas' lead to 36-14.
Texas coach Rick Barnes said Lammert played on a swollen ankle he turned in practice just two days earlier.
"He showed a lot of guts. I told him he'd better shoot the ball every time your open and he did," Barnes said.
Felix opened the second half with two more 3-pointers. He followed the first one with a steal that set up his second in transition. The run ended any chance of a Cowboys rally.
Cowboys coach Travis Ford noted that Texas came in as the second-worst shooting team from 3-point range in the Big 12.
"They go out and make 11," Ford said. "You can't sit around and hope a team misses, you've got to do something about it."
When the teams first met in a January, Smart had 24 points and 11 rebounds and five assists in a Cowboys' victory. His defense helped hold Felix and Taylor to 14 total points.
The Cowboys missed all of that in the rematch.
Sharp-shooting guard Phil Forte, who was Smart's high-school teammate when they won a Texas state championship on the same court, was just 2-of-7 shooting and never got a chance to open up from long-range. Forward Brian Williams was 0-8 and the Cowboys shot just 36 percent for the game.
Ford said he wouldn't use Smart's absence as an excuse for the loss.
"This has nothing to do with Marcus Smart," Ford said. "He wasn't here tonight. We've got to play with what we've got. I don't really even want to talk about it. It doesn't do any good.