Audax Italiano lost a 24-match unbeaten record when they went down to a surprise 2-1 defeat against Deportes Concepcion in the Chilean championship on Wednesday.
Old rivals Gremio and Internacional both need home wins this week to stay in contention in their respective groups in the South American Libertadores Cup.
Caracas FC rode their luck to pull off a stunning upset in the Libertadores Cup on Thursday, beating Argentina's River Plate 1-0 away in Buenos Aires.
Crisis-hit Corinthians had two players sent off and coach Emerson Leao was insulted by fans with chants of 'donkey, donkey' during a 1-1 draw with humble Rio Branco over the weekend.
Mexican teams America and Necaxa both enjoyed away wins in the Libertadores Cup on Tuesday.
Flamengo, Brazil's most popular club, return to the Libertadores Cup after a five-year absence this week with a trip to one of the world's highest professional soccer venues.
Former Brazil striker Romario came off the bench to score a 10-minute hat-trick as Vasco da Gama routed Volta Redonda 6-1 in the Carioca championship on Sunday.
South American champions Internacional, playing their last match before the World Club championship, were thrashed 4-1 at home by Goias in their final league game of the season.
Brazilian league leaders Sao Paulo drew 1-1 at Gremio in a top-of-the-table clash and champions Corinthians beat Cruzeiro 1-0 to climb out of the relegation zone on Sunday.
Uruguay's Nacional overcame a outbreak of mumps in their team to knock defending champions Boca Juniors out of the Copa Sudamericana.
Sao Paulo twice came from behind to beat challengers Parana 3-2 and extend their lead at the top of the Brazilian standings on Thursday.
Internacional have a golden chance to emerge from the shadows of neighbours Gremio when they face Sao Paulo in the second leg of the Libertadores Cup final on Wednesday.
Rioting Gremio supporters set fire to portable toilets, twice forcing their team's match away to Internacional to be interrupted. Play was halted as a thick plume of black smoke rose.
A ball boy was blamed for sparking a brawl in a Peruvian match at the weekend while a player was sent off for hitting a stretcher-bearer as a Colombian game also degenerated into violence.
Brazilian championship leaders Sao Paulo crashed 4-0 at home to Santos on Sunday after fielding their reserve team.
Cienciano striker Miguel Mostto scored four goals in half an hour in the Peruvian championship at the weekend as his team thumped Union Huaral 5-1.