World Cup qualification celebrations in Argentina and Colombia were put on hold until at least the next round of South American fixtures after Uruguay eked out a vital 2-1 victory over Peru in Lima on Friday.
Luis Suarez netted twice to keep Uruguay very much in the picture for next year's finals in Brazil as he moved top of the scorers' standings on 10 goals, one more than Argentina's Gonzalo Higuain.
Higuain will not be able to recover the lead in next week's fixtures as he is suspended for group leader Argentina's visit to improved Paraguay in Asuncion, where Lionel Messi's team will be hoping to secure a ticket to Brazil.
Colombia were on target for a first finals appearance in 16 years after their 1-0 home win over Ecuador in a storm-lashed Barranquilla but Suarez's goals mean they need to avoid defeat against Uruguay in Montevideo on Tuesday to advance.
"This match was highly significant statistically... We had to play with that pressure, that anxiety and then all the rest," Colombia coach Jose Pekerman told reporters after his side moved level on 26 points with Argentina.
Pekerman was referring to the kickoff in Barranquilla being delayed for 90 minutes due to a waterlogged pitch and the start of the second half by 20 more minutes when the floodlights failed.
Chile beat Venezuela 3-0 in Santiago to climb above Ecuador into third place, two points behind the leading duo, with a win that severely dented the visitors' hopes of finals qualification for the first time.
"We made a huge step... We're close (to qualifying). The best thing is that we depend only on ourselves, that gives us tranquillity," Chile goalkeeper Claudio Bravo said.
However, Venezuela (16 points), Peru (14) and even Paraguay (11), who enjoyed a 4-0 rout of Bolivia in Asuncion, could still vie for the playoff berth if Ecuador (21) and Uruguay (19) stumble in the final matches.
"There are nine points still to play for and we must fight... What's changed is that now we don't only depend on ourselves, now we depend on other results," Peru coach Sergio Markarian admitted after his side's defeat.
What Argentina and Colombia have ensured is a place among the top five teams in the nine-nation group since the bottom four can no longer catch them
When the 16-game campaign ends next month, the top four will automatically secure tickets to Brazil while the team finishing fifth will go into a two-legged playoff against either Jordan or Uzbekistan in November for one more berth.
While Colombias visit to Uruguay looks harder on paper than Argentina's match in Paraguay, coach Alejandro Sabella's team are short of four first choice players through suspension: Higuain, central defenders Federico Fernandez and Ezerquiel Garay, and holding midfielder Javier Mascherano.
Playmaker Fernando Gago, back from injury, said Argentina should not concern themselves about Paraguay's improvement under new coach Victor Genes, which has seen them score seven goals in two games including a 3-3 friendly draw with Germany.
"We must keep thinking about ourselves first. We have to think about playing our game, as always," he said.