Ronaldinho scored a classic individual goal but Atletico Mineiro had to settle for a point in a tempestuous clash with Cruzeiro.
Hosts Cruzeiro secured a 2-2 draw when Mateus scored in the 12th minute of stoppage time, after the second half had been held up by supporters throwing various items including bottles onto the pitch.
Referee Nielson Nogueira held up the game in an attempt to restore calm. He sent off three in the match and showed the yellow card nine times.
Cruzeiro went ahead when Wallyson slid in for a close-range opener in the 17th minute, but Leonardo Silva hit a fine equaliser just before half-time - a left-footed strike into the top-left corner from 15 yards.
Tensions among spectators boiled over just before the hour mark. A volley of missiles were flung and referee Nogueira stopped play after they began to hit players.
He dismissed Cruzeiro's Leandro Guerreiro and Atletico's Bernard as they argued, having earlier booked both. Play resumed and Atletico had Pierre sent off in the 89th minute.
But former Barcelona forward Ronaldinho looked to have won it for the nine men in the 90th minute when he produced a vintage run from inside his own half before sidefooting a calm finish into the right corner. Yet the match was far from over and Mateus turned in a low cross in the dying stages to salvage a point.
Atletico nudge a point ahead of Fluminense at the top of the table with their point while Cruzeiro stand eighth.
Gremio climbed to third with a 1-0 win at Internacional, courtesy of Elano's eighth-minute goal.
Luis Fabiano scored both for Sao Paulo in a 2-1 victory away to Corinthians, who had led through Emerson's early effort.
Bottom-of-the-table Figueirense beat Coritiba 3-1 thanks to a hat-trick from Aloisio who scored after 22, 26 and 53 minutes. Anderson Aquino netted in the 33rd minute for Coritiba, who had Everton Ribeiro sent off after 66 minutes.
Bahia drew 1-1 at home against Atletico Goianense, a ninth-minute goal from Fabinho cancelled out by the visitors' Diogo Campos with seven minutes left.
Botafogo drew 0-0 with Flamengo, as did Sport Recife with Nautico Recife.