Palmeiras salvage draw with Avai
Palmeiras are five points ahead of second-placed Sao Paulo with 54 points after 28 matches.
The leaders struggled without midfielder Diego Souza, who is with the Brazil team preparing for Sunday's World Cup qualifier away to Bolivia, and were hard-pressed to cope with Avai's quick counter-attacks in the first half.
William headed Avai into the lead from a ninth minute corner and Emerson increased their lead after half an hour when he headed in a free kick from Marquinhos.
Striker Vagner Love began Palmeiras' recovery when he scored in the 38th minute and keeper Marcos told reporters at halftime: "We're going for all or nothing."
Atletico Mineiro could have climbed to second above Sao Paulo and Internacional but were beaten 3-1 by Botafogo, whose win eased their relegation worries.
Goias remained fifth when they were beaten 3-0 by Cruzeiro, with striker Wellington scoring twice.
Cruzeiro, this year's Libertadores Cup runners-up, climbed to ninth but will be without striker Kleber for about six weeks as he needs hernia surgery, the club said.