The Golden Flashes (10-1, 7-0 Mid-American Conference) clinched the MAC's East Division title when Spencer Keith scored on a 7-yard run with 8:14 left.
The Falcons (7-4, 5-2 MAC) saw a six-game winning streak snapped when Matt Schilz had a fourth-down pass intercepted in the end zone with 21 seconds left.
The final period was a wild scoring affair. KSU's Dri Archer scored on a 74-yard run early in the period to give the Flashes a lead, but BG tied it up when Schilz threw an 81-yard TD pass to Chris Gallon with 14:11 on the clock.
But Schilz was intercepted on BG's next drive, setting up the game-winning score.