OBU built its lead to 6-0 before the Eagles came back to send the game to extra innings.
The Bison scored four times in the second inning on an error and a three-run home run by Michael Cerda.
Daniel Howell homered in the fourth for a 5-0 lead and Dillon Usiak singled in a run for a 6-0 Bison lead in the seventh.
The Eagles got a three-run home run by Heath Steele and an RBI single by Tanner Hessman in the bottom of the seventh it make it 6-4.
Oklahoma Christian tied it with two runs in the bottom of the ninth on a triple by Steele with an outfield error to allow him to score and an RBI single by Dillon Andrews.
OBU took the lead in the top of the 12th when, with two outs, Mitchell Prophet, Daniel Baptista and Howell came up with successive singles with Howell picking up his third RBI of the game.
The Bison had 15 hits in the game, including three by Howell and two each by Greg Nelson, Michael Sliger, Baptista, Prophet and Frankie Rivera.
Johnathan Christensen pitched the first six innings, allowing two runs and striking out seven. Jesus Carlos (1-0) had his first blown save of the season, but picked up the win, striking out four batters in four innings.
Now 22-2 on the season and 6-0 in the SAC, the Bison host Briar Cliff in a 4 p.m. doubleheader Wednesday.
