Lionel Messi has promised Argentina will beat Brazil in their next World Cup qualifying match and get their finals bid back on track.

Barcelona forward Messi was disappointed to be on the losing side against Ecuador on Wednesday, when Argentina slumped 2-0 in Quito.

They stand fourth in the South American qualifying group, the last guaranteed qualifying position, two points above Ecuador and with four rounds of matches remaining.

Argentina will have home advantage when they take on group leaders Brazil on September 5, in their next qualifier, and Messi has rallied his team-mates.

"I have no doubts that Argentina will go on to the World Cup," Messi said.

"We need to beat Brazil and we are going to do it."

Goals from Walter Ayovi, who netted from long range, and Pablo Palacios sank Diego Maradona's team in midweek.

Carlos Tevez had missed a penalty for Argentina while the score was goalless.

Messi explained: "We need to achieve some positive results and we are going to do it.

"I am mad because we did not deserve to lose the game against Ecuador. We produced a good first half and they took the lead with a goal that came from heaven."