As things stand:
The top four teams will automatically qualify for the finals, while the fifth place team will earn a inter-continental play-off spot against New Zealand. Chile, Colombia, Peru, Argentina and Paraguay can all still make it... depending on results.
South America #WorldCupQualifiers log table with one game to go. Argentina is 6th #CONMEBOL pic.twitter.com/4WXM6Ej66j
— Fulltime Score (@fulltime_score) October 6, 2017
Ecuador vs Argentina: Estadio Olimpico Atahualpa, Quito
Ecuador have the opportunity to cause one of the biggest upsets in World Cup history by denying Argentina and Lionel Messi a place at the World Cup for the first time since 1970.
While the hosts have nothing to play for, this is a must win game for Jorge Sampaoli's men.
Brazil vs Chile: Allianz Parque, Sao Paulo
The only positive for Chile here is that Brazil have already qualified for next summer's showpiece event.
A win would secure automatic qualification, a draw should suffice for the play-offs, but a defeat could see 'La Roja' plummet from third to seventh.
Peru vs Colombia: Estadio Nacional, Lima
This is arguably the most decisive fixture. If Peru win this game, they are guaranteed at least a play-off spot, but a draw or a loss would leave their hopes hanging in the balance.
Three points for Colombia would see them over the line, a draw should be enough based on goal difference, while a loss introduces a high possibility of not qualifying.
Uruguay vs Bolivia: Centenario
Only with an incredibly unlikely set of results can Uruguay miss out on automatic qualification. Chile would have to beat Brazil, Colombia would have to beat Peru, or Peru would have to win by nine goals or more, with Argentina producing the same feat.
Bolivia cannot qualify.
Paraguay vs Venezuela: Estadio Defensores del Chaco
Paraguay kept their dreams alive with a dramatic win over Colombia last time out, but will be relying on other results to go their way if they are to qualify for the tournament next summer.
Venezuela cannot qualify.