Marcus Smart left one last impression on Texas Tech, scoring 18 points and leading seventh-seeded Oklahoma State to an 80-62 victory over the ninth-seeded Red Raiders on Wednesday night in the first round of the Big 12 tournament.

Smart also had seven rebounds, seven assists and six steals for the Cowboys (21-11), who built a 46-23 lead by halftime and then cruised into Thursdays' quarterfinal against top-seeded Kansas.

Markel Brown had 20 points, Phil Forte added 14 off the bench and Le'Bryan Nash scored 10 for Oklahoma State, which has never lost in 10 first-round games at the Big 12 tournament.

Jaye Crockett led the Red Raiders (14-18) with 20 points, despite twisting his right knee and limping off the court in the first half. Dejan Kravic added 18 points and 12 rebounds.

Oklahoma State has won five of its last six since Smart returned from a three-game suspension, which was handed down after he shoved a Texas Tech fan during a game in Lubbock. The incident came in the midst of a seven-game skid that put the Cowboys' NCAA tournament hopes in jeopardy.

Now, the Cowboys head into their game against the Jayhawks with a surge of momentum.

Their victory also meant first-year Texas Tech coach Tubby Smith finished with a losing record for the first time in 23 seasons, spanning stints at Tulsa, Georgia, Kentucky and Minnesota.

The Red Raiders actually raced to an 8-0 lead, but the quick start turned out to be merely a charade. Oklahoma State promptly turned up its full-court press, flustered the sloppy Red Raiders into 14 first-half turnovers and went on a 28-5 run to seize control of the game.

Brown and Smart did most of the damage during the decisive run, which ended with a play that might as well have been a microcosm of the entire first half: The Red Raiders' Robert Turner turned the ball over near midcourt, Brown ran out ahead of the pack and leaped up, throwing down a stylish reverse dunk that gave the Cowboys a 28-13 lead.

Oklahoma State slowly pushed its advantage to 40-19 with a few minutes left in the half, then scored the final six points to carry a 46-23 lead into the break.

Texas Tech displayed a faint pulse out of the locker room, scoring the first seven points and forcing Cowboys coach Travis Ford to burn a timeout. But Smart scored to end the run, and then the sophomore -- widely expected to be a lottery pick -- put the game away with a couple more baskets.

Both teams seemed to go through the motions the last few minutes, the Red Raiders preparing for their long offseason and the Cowboys resting up for their marquee matchup with Kansas.

Oklahoma State lost to the Jayhawks on the road early in the conference season, and then beat them in Stillwater earlier this month. Both of the meetings came down to the wire.