Atletico Paranaense's game at home to Fluminense at Curitiba's Arena da Baixada - one of the 12 venues for the 2014 World Cup - ended in chaos on Saturday after the visitors scored in stoppage time to grab a 1-1 draw.
Dozens of Atletico fans gathered around the entrance to the tunnel used by players and officials behind one of the goals, preventing the match officials from leaving the pitch for five minutes.
Television pictures showed that the officials remained in the centre circle surrounded by police as the supporters protested.
At one point, a police official on the pitch pointed a rifle towards the fans. One Brazilian media report said rubber bullets were fired.
Police eventually went into the stands to disperse the supporters and the officials left the pitch surrounded under the protection of officers wielding riot shields.
Paulo Baier gave Atletico the lead after half-time but former Olympique Lyon striker Fred levelled from the penalty which replays suggested was awarded when Lanzini threw himself over in the area.
Atletico, 18th in the 20-team table, were also awarded a controversial penalty in the first half but Cleber Santana's weak effort was effort saved by Diego Cavalieri.
There was also trouble at Cruzeiro where around 250 fans gathered in front of the team's training ground on Saturday to protest the team's recent results.
Fans surrounded the players' cars as they arrived at the training ground and several were insulted, Brazilian media reports said.
