Flamengo hand Palmeiras first home defeat
Palmeiras, previously unbeaten at home, had their lead cut by one point to four over Atletico Mineiro. Palmeiras have gone three matches without victory and not scored in the last two.
Mineiro beat title holders Sao Paulo 1-0 away on Saturday with a second-minute goal by Brazil striker Diego Tardelli to climb into second place. Tardelli joined Flamengo's Adriano as top scorer with 15 goals.
Palmeiras have 54 points from 30 matches, Mineiro 50, Internacional and Sao Paulo 49 and Flamengo 48.
Petkovic struck in the 25th minute when he dribbled in from the left and unleashed a shot into the top corner of Marcos's goal. The much-travelled 37-year-old added his second on the hour when he took a corner and curled the ball directly into the net.
Palmeiras' Paraguayan forward Jose Ortigoza was fouled in the box as he went for a header four minutes from time but striker Vagner Love, back after suspension, hit the penalty over the bar.
At the other end of the standings, Fluminense's Gum stuck a brace past Internacional for a 2-2 draw but they remain rooted in bottom place.