Palmeiras title hopes fade after Marcos blunder
Gremio midfielder Tcheco scored in the 72nd minute when he floated a free kick into the Palmeiras area, the ball eluded a cluster of players and bounced softly into the net as Marcos stayed rooted to his line.
Marcos, who played in Brazil's 2002 World Cup winning team, also annoyed coach Vanderlei Luxemburgo as he joined the Palmeiras attack four times in the closing minutes.
"The crowd liked it but I'm not so sure and I'm going to talk to him about it," Luxemburgo told reporters.
Palmeiras, who started the weekend second in the table, dropped to fourth and fell four points behind leaders Sao Paulo, who won 3-2 at Portuguesa on Saturday.
Sao Paulo have 65 points with four games to play.
Gremio's win took them second with 63 points while Cruzeiro moved into third, ahead of Palmeiras on the number of games won, after beating relegation-threatened Fluminense 1-0 with a second half Ramires goal.
Flamengo, fifth with 60 points, beat Botafogo 1-0 in their Rio de Janeiro derby with a late penalty converted by former Brazil and Manchester United midfielder Kleberson.