William Byron came away with an unexpected victory on Darlington on Sunday after Chastain and Larson clashed at the final restart, with Chastain's tactics once again dominating conversation after the race.

Larson squeezed Chastain into the wall on a restart with 13 laps remaining as he tried to hold on to his lead. Then on the next restart, following a multi-car accident that ensued behind, Chastain attempted a similar move to try and hold off Larson but both cars ended up wrecking.

Larson's Hendrick Motorsport team-mate Byron inherited the lead and held on in overtime for his third win of 2023, while Chastain ended up in the garage as Larson limped home to finish 20th.

Asked to describe the incident, Chastain said: “Full commit. I got really tight and drove up and turned myself. I wanted to squeeze him and wanted to push him up.

“We had been trading back and forth all day and I wanted to push him up for sure, but I definitely did not want to turn myself into the wall. We had a shot, that’s all we can ask for.”

Larson declined interview requests following the race.

Larson’s team owner Rick Hendrick credited Chastain as a very talented driver, but said he needed to tone down his aggression if he ever hoped to win a NASCAR championship.

“I think you can ask any driver in here that he’s wrecked or been involved with him,” said Hendrick.

“He doesn’t have to be that aggressive, and I guess at this point in the race maybe you’re super aggressive, but you just don’t run people up in the fence.

“He’s going to make a lot of enemies. It’s hard to win a championship when you’ve got a lot of paybacks out there.

“With Kyle (Larson), this one and Dover and just Talladega, it’s really getting old with these guys.”

Chastain was involved in a pitlane scuffle at Kansas with Noah Gragson after the Legacy Motor Club driver confronted him after the race.

He has also had multiple confrontations with Denny Hamlin, the Joe Gibbs Racing driver having points retrospectively deducted after he admitted on a podcast to intentionally walling Chastain at Phoenix earlier this year.