Ouellette had 2- and 1-yard scoring runs in the first half to help Ohio (5-5, 3-3 Mid-American) take a 17-0 lead. Josiah Yazdani hit the second of his three field goals and Derrius Vick had a 9-yard run to make it 27-0 in the third quarter.
The Bulls (3-6, 1-4) finally scored with 3:54 left in the third quarter on Joe Licata's 12-yard pass to Ron Willoughby, which came after Ohio lost a fumble at its 19. But Ohio responded with another field goal and Dorian Brown's 3-yard TD run for a 37-7 fourth-quarter lead.
Buffalo didn't top 100 yards in offense until midway through the fourth quarter. The Bulls finished with 134 yards of offense and seven first downs. They had four turnovers.
Licata tied Drew Willy for the school's career touchdown pass record with 52.