Ronaldinho is blaming the referees for keeping him away from his first Brazilian league title.
Atletico Mineiro was held to a 1-1 draw by Flamengo in a controversial match on Wednesday, dropping eight points behind leader Fluminense with five rounds left.
The two-time world player of the year loudly complained of a penalty on him in the first half, saying the missed call would have changed the final result.
The play happened in the 10th minute at the Independencia Stadium in Belo Horizonte, when Ronaldinho prepared for a shot from inside the area. He was shoved away just as a defender came for the ball, dropping to the ground and immediately raising his arms to complain. The referee was just behind the play, but let it continue.
"It hurts," Ronaldinho said. "We came out attacking and looking for that early goal. We got the penalty, but again the referee didn't make the call. We leave the field frustrated. A penalty that early would have changed the entire match."
He admitted Atletico's title chances took a big hit because of the home.
"It's frustrating because we needed the win. (Fluminense) already had a good advantage coming in," he said. "It was a mistake that's costly for us."
Atletico, seeking its first league title since 1971, had opportunities to get the win despite the alleged missed call, especially after Flamengo defender Wellington Silva was sent off with a second yellow card in the 43rd. Ronaldinho didn't have one of his best matches, but nearly scored an 89th-minute winner with a free kick that hit the crossbar.
Ronaldinho and Atletico have been protesting against the refereeing for quite some time, saying there have been too many calls against the team and too many in favor of Fluminense.
Atletico may actually be punished by Brazil's sports tribunal after fans used banners and even a mosaic criticizing the local football federation and accusing the referees of benefiting Fluminense throughout the season.
"I wished I could come here and talk just about the game, but it's not possible after what happened out there today," Atletico Mineiro coach Cuca said Wednesday. "This championship is being marked by the refereeing mistakes. It's unfortunate."
The teams drew 0-0 in a controversial match the first time they played earlier this year, when it was actually Fluminense who had reason to complain after striker Fred had an 88th-minute goal mistakenly waved off for offside.
Ronaldinho has been thriving since transferring to Atletico Mineiro from Flamengo earlier this year. His good performances prompted Brazil coach Mano Menezes to say Tuesday that the door remains open for Ronaldinho's return to the national team if he keeps playing well.
Ronaldinho helped Brazil win the 2002 World Cup in South Korea and Japan, and played in the 2006 tournament in Germany. He was not picked for the squad for the 2010 World Cup in South Africa.
Ronaldinho is seeking his first Brazilian league title after spending a decade in Europe, where he starred for Paris Saint-Germain, Barcelona and AC Milan. He returned to Brazilian football in the beginning of 2011.