Chastain, who led a race-high 31 laps, took the checkered flag for the first time in his 121st NASCAR Cup Series starts.
After Allmendinger pushed him wide on the final lap, Chastain quickly returned the favor. Alex Bowman, who had joined the battle, was caught in the crossfire. Allmendinger spun and Bowman went off track, allowing Chastain to get away and capture the race win.
There were nine cautions during the race. Nine different drivers took turns out front and there were 13 lead changes.