Oklahoma, the No. 4 seed, will face fifth-seeded Oklahoma State in the Big 12 Baseball Championship on Wednesday at Chickasaw Bricktown Ballpark.
Saturday was the final day of the Big 12's regular season. League champion Baylor wrapped up the No. 1 seed in the tournament. Texas A&M finished second after sweeping OSU at Reynolds Stadium, and Texas is the No. 3 seed.
Missouri finished sixth, Kansas was seventh and Kansas State earned the final berth in the tournament by winning the final series against ninth-place Texas Tech.
Times for the Big 12 tourney games have yet to be determined.
Texas A&M 5, OSU 4
Texas A&M scored three runs in the top of the ninth inning to complete a three-game sweep at Oklahoma State.
OSU (32-23, 13-11 Big 12) has lost 11 straight against the Aggies.
A&M's Daniel Mengden hit a three-run home run in the top of the ninth, then took the mound in the bottom half of the inning to earn the save.
Saulyer Saxon was 2-for-5 with three RBIs for OSU.
OU 13, Samford 3
Oklahoma scored a season-high 13 runs to take the final game of a three-game series in Norman.
The Sooners (35-21, 13-10 Big 12) jumped out to a 2-0 lead in the first inning and never looked back.
Max White had three hits and two RBIs, and Hunter Lockwood drove in three runs for OU.
Sooner starter Damien Magnifico improved his record to 3-1.