Sao Paulo, on course for a fourth successive title, are three points ahead of arch rivals Palmeiras with three matches to go.
Palmeiras were held to a 2-2 home draw to bottom side Sport Recife in midweek, their third match in a row without a win.
Sao Paulo defender Andre Dias (pictured) and midfielder Hugo came to blows over marking duties at a corner in the 15th minute at the Morumbi. They had to be separated by a team mate and both were booked.
Dias said later it was a misunderstanding in the heat of the match and that they had patched up their differences.
Jorge Wagner put Sao Paulo ahead in the 25th minute when he netted the rebound after Vitoria's Colombian keeper Julian Viafara parried a shot from Washington.
Hugo headed the second four minutes after the interval from a cross by Hernanes from the left.
Sport Recife are looking to get the Palmeiras result annulled. They have taken a complaint about Palmeiras' late second goal to a sports tribunal.
Television replays showed referee Elmo Cunha whistled for offside and the defence stopped playing before Palmeiras defender Danilo scored. Cunha allowed the goal to stand because the linesman did not raise his flag. The referee has been suspended until the end of the season.
Sao Paulo have 62 points from 35 matches and Palmeiras 59. Third-placed Flamengo, away to lowly Nautico on Sunday, have 57 and Atletico Mineiro make up the top four with 56 despite losing 2-1 to Coritiba.
Cruzeiro looked set to get into the top four when they led Gremio at home in Belo Horizonte with a penalty converted by Gilberto and visiting players Tulio and Fabio Santos were sent off in the final five minutes.
But two minutes into stoppage time, Gremio's Argentine strikers combined for the equaliser in a 1-1 draw, German Herrera scoring from Maxi Lopez's pass to leave Cruzeiro with 55 points.
