Brazil superstar Neymar returns from suspension to face an injury-hit Argentina Thursday as South America's qualifying campaign for the 2018 World Cup resumes with a showdown between the bitter continental rivals. Neymar was forced to sit out Brazil's opening two qualifiers last month — a 2-0 defeat to Chile followed by a 3-1 victory over Venezuela — following his four-match suspension at the Copa America in June. But the talismanic striker is now back and available for Brazil as the five-time world champion heads to Buenos Aires to face an Argentina side which took only one point from its first two games. Argentina suffered a shock 2-0 defeat at home to Ecuador in its opening game and then labored to a goalless stalemate against Paraguay in Asuncion. Those results have piled the pressure on beleaguered Argentina manager Gerardo ‘Tata' Martino, whose position had already come under scrutiny after his star-studded side's failure to win the Copa America. Martino's preparations for Thursday's showdown at the Estadio Monumental have been thrown into turmoil by an injury crisis which has deprived him of an array of attacking talent. Captain Lionel Messi had already been ruled out after suffering a long-term knee injury in September. Manchester City striker Sergio Aguero is also unavailable while Carlos Tevez is rated as doubtful after suffering a knee problem. Boca Juniors striker Tevez skipped training Monday and is struggling to be fit according to press reports in Argentina. Paris Saint-Germain midfielder Javier Pastore is also a concern after suffering a calf injury. Brazil veteran Kaka, restored to the squad by coach Dunga earlier this year, has urged the Selecao to draw on the memory of their 3-1 win in Argentina during a 2009 World Cup qualifier as they prepare for Thursday's clash. Elsewhere Thursday, Ecuador and Uruguay will meet in a top-of-the-table meeting involving two sides with 100 percent records. Uruguay, which is still missing Luis Suarez as he serves out the remainder of his 2014 World Cup biting ban, will be able to recall striker Edinson Cavani, suspended during the Copa America for his lurid altercation with Chile's Gonzalo Jara. The Uruguayans defeated Bolivia and Colombia in their opening games while Ecuador is brimming with confidence after stunning Argentina before a further win over Bolivia at home. Uruguay coach Oscar Tabarez has urged "La Celeste" to reproduce the decisiveness shown in their opening victories as they head for an awkward assignment at altitude against Ecuador Thursday. Ecuador meanwhile is facing injury problems of its own, with English Premier League duo Enner Valencia and Antonio Valencia both missing along with attacking midfielders Michael Arroyo and Renato Ibarra. In Thursday's other marquee match, Copa America champion Chile takes on a Colombia side which has Real Madrid superstar James Rodriguez fit and available for selection once more. Elsewhere Thursday Bolivia and Venezuela meet in La Paz seeking their first points of the qualifying campaign. Peru and Paraguay will face each other Friday in Lima.