Brazil is in, and over the next week three more South American countries will join the five-time champions at the World Cup in Russia.
The fifth-place team from the region will also keep its chances alive, facing a playoff next month against New Zealand. That winner will also advance.
With two matches to play, Uruguay and Colombia are in the best shape to join Brazil at the World Cup. The biggest shock could be two-time champion Argentina, which will battle for a spot against Peru, Chile, Paraguay and Ecuador. Bolivia and Venezuela have been eliminated.
Argentina, the runner-up three years ago in Brazil, has not missed a World Cup since 1970.
Here's a look at the countries and matches set for Thursday and next Tuesday.
Argentina and Peru play Thursday at Boca Juniors' La Bombonera stadium, among the world's most hostile venues for visiting teams. It's the first World Cup qualifier there in 20 years.
Both countries have 24 points, and a victory by either would be a giant step toward qualifying. A slip, and Argentina will have to win the final match in Quito, Ecuador, where the altitude of 2,850 meters (9,350 feet) is a burden for visiting teams.
Peru, coached by Argentine Ricardo Gareca, is at home to Colombia in its final game.
Argentina will be without Sergio Aguero for both matches after he fractured ribs in a car accident last week. New coach Jorge Sampaoli has been unable to lift the team, which has drawn its last two matches, against Uruguay (0-0) and Venezuela (1-1).
Uruguay is in great shape. It has 27 points and second place in the standings, 10 points behind Brazil. The team finishes qualifying at Venezuela, and at home against Bolivia - the two countries that are already eliminated.
Depending on other results, a draw at Venezuela on Thursday might be enough to guarantee Uruguay a place in its third straight World Cup.
Colombia has 26 points and beating Paraguay in the coastal city of Barranquilla could be enough to secure a place at its second straight World Cup. That would also eliminate long-shot Paraguay.
''We're fired up, but relaxed, knowing that this group can win the match and bring happiness to Colombia,'' defender Davinson Sanchez said.
The two-time defending Copa America champion has only 23 points and is teetering on the edge. Chile is home against Ecuador on Thursday, and then must beat Brazil next week in Sao Paulo.
Chile has lost its last two matches, against Paraguay and Bolivia, an indication of the state of play.
Peru has 24 points and has won three games straight to get back into contention. After the match in Buenos Aires, it finishes at home with Colombia.
''We're going to arrive at that final game in great shape,'' Argentina-born coach Ricardo Gareca said. ''We've got this far with our determination.''
Peru last reached the World Cup in 1982 in Spain.
Brazil is already in, and will surely test reserves in Thursday's match in the thin air of La Paz. Look for the regulars to face Chile next week in Sao Paulo.
Brazil coach Tite is undefeated in 10 qualifying games, and has won nine of them.
Paraguay with 21 points, and Ecuador with 20, will need to win their final two matches and get help from others to have any chance. Bolivia and Venezuela are out.