The match between the two main clubs in Porto Alegre is known as the Grenal but Gremio withdrew from the match at Inter's Beira-Rio stadium after rocks smashing through coach windows hurt players.
Gremio posted a picture of Mathias Villasanti being taken to hospital in an ambulance. It also showed photographs of smashed coach windows and a rock bigger than a fist it said hit the Paraguayan midfielder. "After the cowardly and absurd agression suffered by our delegation we have told the Gaucha Football Federation of our decision not to go ahead with the Grenal derby this Saturday," Gremio said.It was the second time in three days that a coach carrying a Brazilian team had been attacked on its way to a game, after Bahia players were hit before Thursday night's match against Sampaio Correa in Salvador.