Chastain, who came into the weekend stating he needed to “wreck less and win more”, claimed pole position and ended a more than year-long winless streak in Nashville.
With 70 of 300 laps remaining, Chastain ran down Denny Hamlin to take the lead then stayed out front through the final round of pitstops.
Martin Truex Jr closed up to Chastain’s rear bumper multiple times in the last 50 laps as the two navigated lapped traffic, but Chastain beat him to the chequered flag by 0.789 seconds to secure the win.
The win is the third of Chastain’s career and comes during a season in which he has performed well on the track but has been caught up in run-ins with other drivers.
Most notably, Chastain lost a chance of victory at May’s Darlington race when he crashed into Kyle Larson while leading, and he came in for criticism from Hendrick Motorsports executive Jeff Gordon and Larson’s team owner Rick Hendrick.
“I got to tell you, this is incredible,” Chastain said, after doing a burnout on the frontstretch and smashing a watermelon. “This is why every little kid out there anywhere in the world, when you get criticised, and you’re going to if you’re competitive, they will try to tear you down. You will start believing you can’t do it.
Race winner Ross Chastain, Trackhouse Racing, Chevrolet Camaro
Photo by: John Harrelson / NKP / Motorsport Images
“You have to go to your people, trust in the process, read your books, trust the big man’s plan upstairs, just keep getting up and going to work. I got to tell you, a lot of self-reflection throughout all this.
“I had a group that believed in me and they didn’t let me get down. They bring rocket ships and I just try to point them to victory lane.”
After losing touch of the victory battle, Hamlin ended up third and ahead of Hendrick Motorsports’ Chase Elliott, as his team-mate Kyle Larson rounded out the top five.
William Byron took sixth in front of Christopher Bell and Erik Jones, as Kyle Busch and A.J. Allmendinger completed the top 10.
Truex Jr retains the overall points lead in the NASCAR Cup standings ahead of Byron and Chastain.
NASCAR Cup Nashville – race results (300 laps)