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.
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.
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.