Argentina and Colombia will look to wrap up qualification for next year's World Cup as South America's battle for places at the finals in Brazil enters the home stretch.

Leader Argentina has a bye for Friday's round of fixtures but will be able to guarantee its 11th consecutive World Cup appearance with victory over bottom team Paraguay in Asuncion on Tuesday.

Second-placed Colombia, meanwhile, will go level on points with the Argentines and stand on the threshold of a first World Cup appearance in 16 years with a win over third-placed Ecuador on Friday.

The Colombians' preparations for their clash with Ecuador have been disrupted by an injury to star striker Radamel Falcao, who twisted an ankle in Monaco's clash with Marseille in Ligue 1 last weekend.

Colombia team doctor Carlos Ulloa said Falcao was responding well to treatment but rated the forward as doubtful for Friday's showdown with its bitter rival at the Estadio Metropolitano Roberto Melendez.

The encounter is likely to be an emotion-filled affair with Ecuador returning to competitive action for the first time since the shock death of popular international Christian Benitez, who died suddenly of heart failure in July.

Benitez scored the winning goal in Ecudor's 1-0 victory when the two sides met in Quito earlier in the qualifiers, and coach Reinaldo Rueda said his grieving squad is still struggling to come to terms with the loss of the striker.

"These last three or four weeks have been very tough and intense, as well as extremely painful," Rueda, whose father passed away shortly before Benitez's death, told FIFA.com in a recent interview.

"I don't know if over time it will be different. Dealing with the grief has been difficult, but you just have to keep going."

Rueda, who is Colombian, also acknowledged he expects to feel mixed emotions as he returns to his homeland as Ecuador manager.

"My feelings are difficult (to reconcile). It will be a conflict from an emotional point of view, even from a family one," he said.

"That's the kind of thing this job demands of you, and we need to be honest about it. However, we're playing for ourselves and our qualification."

With Ecuador and Colombia setting the pace behind Argentina, which along with Chile is in a pole position to secure one of the top four automatic qualifying places, a fierce battle for fifth is unfolding.

Two-time World Cup winner Uruguay, beaten semi-finalist in 2010, is in a ferocious dogfight to qualify which leaves it with precious little margin for error as it prepares to face Peru in Lima.

Peru could leapfrog over the Uruguayans with a win, which would most likely leave Uruguay needing to take points from its difficult run-in -against Colombia, Ecuador and Argentina - to keep its qualifying bid alive.

Uruguay's Paris Saint-Germain striker Edinson Cavani said Friday's match in Lima and Tuesday's game against the Colombians in Montevideo could prove decisive.

"Considering where we are in the classification, these two games are going to be key for us," Cavani said.

"Peru have quality but I know we also have the weapons to fight it," he said.