Internacional captain Andres D'Alessandro and his Gremio counterpart, Maicon Souza, needed to be restrained by officials from going after each other during the coin toss before their Brazilian city derby.
The two players had a heated exchange in the prematch protocol for Sunday's league game at Porto Alegre's Bela-Rio stadium.
They refused to shake hands and Argentine midfielder D'Alessandro twice had to be restrained by an official after making aggressive moves towards Maicon.
Real Madrid left-back Marcelo has wished Brazil teammate Neymar a speedy recovery from a foot operation and said he is confident that the Paris Saint-German forward will play at this summer's World Cup.
Neymar was discharged from a hospital in Belo Horizonte on Sunday after undergoing successful surgery on a fracture of his fifth metatarsal in his right foot.
The operation went well and Neymar is expected to be out of action for three months.
"Neymar knows that people are with him, that Brazil is...