Watch: NASCAR driver throws punch after heated exchange at Martinsville

Tempers often flare when NASCAR visits Martinsville Speedway, and that was the case on Saturday. 

Following a hard-fought Xfinity Series playoff race, drivers Chandler Smith and Cole Custer — who finished third and fourth, respectively — raced each other hard in the closing laps. 

With under 40 laps to go, Smith — who needed a win to advance to the Championship Four at Phoenix — was running third, with Custer in second. After being patient with Custer and tapping his bumper, Smith finally had enough, moving Custer up the track to take over second place. 

When presented with the opportunity to restart behind Smith on lap 227, Custer — who restarted fourth — moved Smith up the track, sending Smith's No. 81 from second to outside of the top-five. 

While another caution followed, Smith didn't have enough time nor speed to get around Aric Almirola for the race win. The loss knocks Smith out of the playoffs, and it could serve as the race that effectively ends his career, at least in the short term. Meanwhile, Custer advanced to the Championship Four on points and will have the chance to defend his 2023 title on Nov. 9. 

After the race, Smith made his feelings clear to Custer. Apparently, a verbal altercation wasn't getting his point across, as he proceeded to throw a punch at Custer. 

The altercation was quickly broken up by officials and crew members, and the two drivers were separated before doing their post-race interviews.