Former Brazil coach Luiz Felipe Scolari told a reporter he was a clown and suggested the referee had used television replays to change a decision after his Palmeiras team were held 1-1 by Atletico Mineiro.
'Big Phil' lost his cool during the post-match press conference, broadcast on Brazilian television, when he was asked why he had fielded midfielder Jorge Valdivia.
The Chile international has been plagued with muscular problems recently and was substituted after only 18 minutes of the game.
"No, no, no, no," said Scolari, grimacing and shaking his head when reporters suggested he had made the wrong decision.
"You lot really are a pain," he said, screwing up his face. "He played for 18 minutes, that's good for me.
"Go you and interview the doctor," added Scolari, his eyes rolling menacingly. "You lot are just clowning around and you're one of the biggest clowns," he said, gesturing towards one television reporter.
The pressures of coaching in Brazil appear to have brought back Scolari's more volatile side.
The former Chelsea boss was also angry after his team were awarded a penalty, only for the referee to change his mind after speaking to his assistant.
"We were told the referee or linesmen received information by radio from somebody outside the four lines (pitch)," he said.