Rush scored the game-winner for the Chippewas (5-4, 3-2 Mid-American Conference) on a 7-yard pass to Titus Davis with 8:08 left to play. Saylor Lavallii added 80 yards rushing and two touchdowns on 21 carries.
Lavallii scored twice from short yardage in the first half to give Central Michigan a 14-7 halftime lead. Early in the third quarter, Buffalo's Joe Licata tied the game, 14-14, on a 6-yard TD pass to Malcolm Robinson.
Brian Eavey missed the extra point following Rush's fourth-quarter touchdown pass and the Chippewas led 20-14.
Licata finished with 21-of-35 passing for 233 yards and a pair of touchdowns for the Bulls (3-5, 1-3).