Ex-Formula 1 driver Felipe Massa has apologised after one of his team-mates brawled with one of his rivals after they crashed out of the 500 Milhas de Kart event.
Rodrigo Dantas, who was driving for Massa's team, was holding up former World Series by Nissan and A1 Grand Prix racer Tuka Rocha, who was lying second in the race and trying to catch leader Massa.
After repeated contact between them, Rocha punted Dantas off the track, with both karts coming to rest against the tyre barrier.
The pair got out of their karts and squared up physically. Dantas then pinned Rocha to the ground while repeatedly punching his helmet.
Security guards had to end the fight, which resulted in disqualification of all karts in the two teams - MDG Matrix and Sambaiba Centerbus Racing.
There had previously been a running battle between the teams throughout the race, which lasted just under 12 hours, and Massa said this was the catalyst for what transpired.
"From what I saw, the whole team should be disqualified," Massa said of the previous encounters between them. "But that did not happen, and what happened next was a war inside the track.
"For me, this is very sad and sadder still to see my team within that. It was not my decision - I was driving the [leading] kart - but I apologise to everyone for what happened, because I have never seen anything like it in my career.
"The competition is inside the track, but never in this way."
Event organiser Felipe Giaffone said after the race: "We will take appropriate steps to banish the culprits from these unfortunate scenes."
Barrichello inherits victory
Rubens Barrichello's Hero # 71 team was the ultimate winner of the event.
The team had been two laps behind the duel for the lead and inherited victory after the disqualifications.
The team comprised Barrichello, Giaffone, Rafael Suzuki, Gary Carlton, Diego Nunes, Beto Cavaleiro, Porto Kiko, Arthur Leist, Rafael Martins, Dudu Barrichello and Joao Cunha.
"It's a unique and incredible situation to win the 500 Miles with my son," said Barrichello. "I love him so much and all of our team are to be congratulated for the great work they have done."
Son Dudu said: "It was a strange ending, something I had never really seen happen on the track, but I'm really happy for the win and for getting on the podium first with my dad."