Argentina and Brazil both lost their opening World Cup qualifiers on Thursday as the South American campaign for Russia 2018 started in unexpected fashion.

Argentina, who were missing injured Barcelona striker Lionel Messi, were surprisingly beaten 2-0 at home by Ecuador, a side 30 places behind them in the FIFA rankings.

Frickson Erazo got Ecuador's first goal after 80 minutes and Felipe Caicedo doubled their lead when he finished off a quick counter attack just a minute later.

"It's no use just looking at the score," Argentine midfielder Javier Mascherano said after the match. "We were never superior to them."

"We could never find answers to the problems that Ecuador gave us, we were never comfortable," he added.

To compound Argentina's misery, Manchester City striker Sergio Aguero limped off injured midway through the first half and will miss next Tuesday's match away to Paraguay.

Things were no better for five-time World Cup champions Brazil, who went to Chile looking to rebuild their reputation after being hammered 7-1 by eventual winners Germany in last year's semi-final.

However, coach Dunga's side could not match the relentless running of a Chilean team that had the momentum with them after winning the Copa America in July.

Hoffenheim striker Eduardo Vargas volleyed home a cross in 72 minutes to put the home side ahead and then Arsenal's Alexis Sanchez got a second from close in with a minute remaining.

Earlier in the evening, Uruguay, Paraguay and Colombia all made wining starts to their campaigns.

Uruguay overcame the thin air at high altitude to beat Bolivia for the first time in 10 qualifiers in La Paz.

Defenders Martin Caceres and Diego Godin scored for Uruguay in the absence of suspended strikers Luis Suarez and Edinson Cavani, while the frustrated Bolivians had Jair Torrico sent off after 71 minutes.

Colombia, meanwhile, beat Peru in temperatures of 35 degrees Celsius and high humidity in Barranquilla.

Teofilo Gutierrez scored from a 36th minute header following a corner for 2014 World Cup quarter-finalists Colombia, who were without injured playmaker James Rodriguez.

Peru striker Paolo Guerrero hit the post early in the second half and Colombia goalkeeper David Ospina brilliantly saved Christian Cueva's free kick before substitute Edwin Cardona scored the second goal in added time.

"We had chances to draw the match, my team finished in good physical and footballing shape, I liked how we played though not the result," said coach Ricardo Gareca, who is looking to qualify Peru for their first finals since 1982.

Paraguay, recovering from their disappointment at not reaching the 2014 tournament in Brazil, scored an 85th minute winner from Derlis Gonzalez for a 1-0 victory away to Venezuela.

The qualifiers continue next Tuesday, with Argentina away at Paraguay, Brazil at home to Venezuela and Ecuador looking to build on their great start at home to Bolivia.

Uruguay take on Colombia in Montevideo and Peru host Chile.