Sadler passed Keselowski on a restart with 18 laps to go, but officials ruled that Sadler went too early and black-flagged him. Sadler stayed on the track for several laps, apparently hoping officials would reconsider the penalty, before finally coming in with 12 laps to go and giving up the lead to Keselowski.
Keselowski went unchallenged to the finish on the historic 2.5-mile oval.
Sam Hornish Jr. was second, followed by Ty Dillon, Denny Hamlin and Austin Dillon.
Sadler finished 15th.