Eight-man Sao Paulo draw at Gremio
Strikers Dagoberto and Borges were sent off seconds apart and midfielder Jean was shown the red card in stoppage time in the match against the league's only team yet to be beaten at home.
Sao Paulo, looking for a fourth successive championship title, have 59 points after 34 matches, a point ahead of Palmeiras, who visit bottom team Fluminense at the weekend.
Gremio went in front after 25 minutes when defender Rafael Marques headed in a free kick from Douglas Costa but seven minutes later a shot by Dagoberto took a deflection off Marques and went in for the equaliser.
Substitute Borges was the first to be sent off - 12 minutes after he came on - for a second booking in the space of two minutes. Dagoberto was shown a straight red card in the next minute for a bad tackle on Tulio.
Jean was sent off for a second yellow card.
Third-placed Atletico Mineiro (56 points) are at home to Flamengo (54) at the weekend in a tight race for the title and four Libertadores Cup berths.