After watching his Hendrick Motorsports team-mate Kyle Larson – who dominated most of the race – wreck out late, Byron got around Bubba Wallace and Chase Briscoe on a restart with five of 267 laps remaining to take the lead for the first time.
Erstwhile leader Wallace had chosen the outside lane for the final restart and got side-by-side with Briscoe, with Byron lined up behind the Stewart-Haas Ford. Briscoe edging Wallace's 23XI Toyota deeper to the outside opened the inside lane, which Byron exploited to pass both for the lead.
Byron then held off a late charge by Ross Chastain (Trackhouse Chevrolet), ultimately clearing him by 1.863 seconds to take his sixth win of the season and secure the milestone win for Hendrick, whose first Cup victory came in 1984 with Geoffrey Bodine.
The 25-year-old therefore advances to the semi-final round of the playoffs regardless of how he finishes in the next two races at Talladega and the Charlotte Roval, with seven more spots up for grabs.
Byron admitted that Larson "really deserved this one" and explained afterwards that he had found life tough in the cockpit in the heat.
He said: "It was awesome to get our car to the front, I loved clean air. We just fought through traffic all day and our [car] was just tight back in traffic but had good pace.
“This was one of those hot days, it felt like I was playing football and went through two-a-days, just wanted to quit.
"It was a grind it out day and our team was there at the end. I'm really proud of this one as hot as it was and as tough as it was.”
Source: Autosport