Byron made sure he was prepared for the fireworks he thought could happen.
Byron moved in front when Chastain and Larson wrecked while racing for the lead on a restart with six laps left, then held off Kevin Harvick in overtime to win the Goodyear 400 at Darlington Raceway on Sunday.
"We talked about it under the caution," Byron said of a potential dustup. "I didn't think that they would wreck, but obviously it happened and we rolled on by."
Chastain and Larson have raced each other tooth-and-nail this season with incidents impacting potential wins at Talladega and Dover heading into the track "Too Tough to Tame."
It didn't take a rocket scientist -- Byron is taking college courses at Liberty University -- to know the two might tangle again.
It was a measure of retribution for Byron, who was two laps from victory in this race year a year ago until he was shoved out of the way by eventual winner Joey Logano.
"It's pretty amazing," Byron said. "Things have a way of working out."
He got away cleanly from Harvick on the green-white-checkered finish for his third win this season and seventh of his career.
Harvick was second and Chase Elliott third, his best finish since returning to NASCAR from a broken leg while snowboarding.
It was the 100th win for Hendrick Motorsports' No. 24 car and the organization's first victory at Darlington since Jimmie Johnson won the 2012 race.
It looked like 2021 champ Larson or points leader Chastain had the strongest cars and figured to be there at the end. Instead, Chastain was alongside Larson during a restart and admitted trying to squeeze his competitor against the wall in turn two. Both wound up wrecking.
Larson finished 20th and Chastain, who punched Noah Gragson in a pit-road confrontation a week ago at Kansas, was 29th.
"I wanted to squeeze him, I wanted to push him up, we've been trading back and forth all day. I wanted to push him up for sure," Chastain said.
Larson's crew chief, Cliff Daniels, angrily said on the radio, "Three races he's taken us out of."
"Children," TV analyst and racing great Bill Elliott said. "You put 'em in a sandbox together and they can't play."
Larson moved into the lead when Denny Hamlin went to the pits with 30 laps remaining and was in prime position for victory until tangling with Chastain.
"He doesn't have to be that aggressive," winning owner Rick Hendrick said of Chastain. "He's going to make a lot of enemies."
Martin Truex Jr. started from the pole and led 145 of the first 151 laps before he was clipped by Chastain at the end of stage.
Chastain led 93 laps and has not won since Talladega in April 2022, a stretch of 39 races.