Allmendinger moved into the lead for the first time in the race when he passed Kyle Busch on the start of the final stage, but had to navigate five restarts over the final 31 laps.
With less than 10 laps to go, William Byron moved past Busch into the second and closed to Allmendinger’s rear bumper several times, but the 41-year-old veteran deftly held him at bay and won by 0.666 seconds.
Busch, Keselowski, Wallace and Chastain were the four drivers lowest in points without a victory following the race and have been eliminated from playoff contention.
With that quartet out of the playoffs it means Byron, Tyler Reddick, Chris Buescher, Martin Truex Jr., Denny Hamlin, Christopher Bell, Kyle Larson and Ryan Blaney kick off the semifinal round of the championship fight next Sunday in Las Vegas.
The win is the first for Allmendinger and his #16 Kaulig Racing team this season, which had been a disappointment as he failed to qualify for the playoffs.
Source: Autosport