Eddie Cervantes (4-5) shut out the Bison on seven hits, including three by Jorden Newton. OBU left seven runners on base and had two caught stealing.
The second game was a much brighter story for the Bison as Baptista had a grand slam and a three-run home run to seal the regular season conference RBI title with 69.
USAO scored an unearned run in the top of the first for a 1-0 lead.
Greg Nelson doubled and Mitchell Prophet walked with two outs before Baptista launched his three-run home run to right for a 3-1 lead. Michael Sliger reached on an error and scored on a double by Michael Cerda to make it 4-1.
USAO scored on an RBI singles by Romus Cezar and Brian Vigo in the second and third to make it a 4-3 game.
The Bison scored twice in the fourth on an RBI double by Dillon Usiak and a sacrifice fly by Baptista.
OBU got three runners aboard without a hit to start the sixth inning before Baptista launched his grand slam for his 14th home run of the season.
The Bison had nine hits in the game, led by Baptista with three and Cerda with two.
Now 42-12 overall and 22-8 in the SAC, the Bison open the Sooner Athletic Conference Tournament Wednesday.
The tournament will have two pools of four teams each at OBU and Oklahoma City. Games will be played at 2 and 6 p.m. at each site, each day, round-robin style with the pool winners meeting at OBU at 1 p.m., Saturday, for the championship game.
At OBU’s pool are the Bison, Rogers State, USAO and St. Gregory’s. The other pool has Oklahoma City, Lubbock Christian, Northwestern and Southern Nazarene.
The full schedule will be available sometime this weekend.