Chile and Brazil scored controversial goals in a 1-1 World Cup qualifying draw on Sunday while Colombia hammered Uruguay 5-0 to condemn their opponents to their third successive defeat in the competition.
Argentina missed a chance to go top of the South American group when they were held to a home draw by Paraguay while Peru and Venezuela also shared a goalless stalemate in Lima.
The weekend's results left the race for the 2006 World Cup in Germany wide open with only three points separating second-placed Argentina and seventh-placed Peru.
The top four nations qualify directly for the World Cup finals while the fifth plays off against the winners of the Oceania region for another place.
Brazil stayed top after their draw on a cold night in Santiago.
The world champions, who won and converted three penalties when they beat Argentina 3-1 last Wednesday, enjoyed another slice of fortune when Luis Fabiano gave them a 16th-minute lead with television replays suggesting he was offside.
But their luck ran out with one minute to go when Rodrigo Perez tumbled in the penalty area. Although replays suggested no contact was made, Argentine referee Horacio Elizondo pointed to the spot and Reinaldo Navia converted.
"Everyone saw it wasn't a penalty. Even the Chilean players said it wasn't a penalty," Brazil defender Roberto Carlos told reporters.
The point kept Brazil top with 13 points from seven games, followed by Argentina (12), Chile and Paraguay (11), Ecuador and Venezuela (10), Peru (9), Colombia and Uruguay (7) and Bolivia (6).
Colombia, who lost four of their first six matches, and Uruguay, beaten at home by Venezuela and Peru in their last two games, met in Barranquilla and it was the Uruguayans who came off worse.
Victor Pacheco and Tressor Moreno scored two quick goals as Uruguay went two down in 20 minutes for the second game in a row.
Pacheco added another first-half strike before John Jairo Restrepo skipped through the defence for a brilliant fourth in the 81st minute. Sergio Herrera tapped in another five minutes later, the 11th goal conceded by Uruguay in three outings.
Argentina fielded four strikers, giving Barcelona's Javier Saviola a rare start, and dominated their match against Paraguay in Buenos Aires but had to be content with a goalless draw.
It was the fourth time in a row Paraguay have forced a World Cup qualifying draw in Argentina, whose last win in the fixture came in October 1973.
Paraguay had midfielder Angel Ortiz sent off in the 61st minute but held out thanks to brilliant goalkeeping by Justo Villar.
"In the first half, we had a lot of chances and couldn't take them," said Argentina striker Carlos Tevez. "In the second, they closed us down very well and made it difficult to get into the penalty area."
Peru had a similarly frustrating time against Venezuela, for whom goalkeeper Gilberto Angelucci was also in inspired form.