"We have to get together and go forward because Argentina can't stay out of the World Cup," the Barcelona forward said.
Coach Diego Maradona's team, who lost their last two qualifiers 3-1 to Brazil and 1-0 in Paraguay, are in fifth place in the South American group, which is a playoff berth.
"I alone won't win a match...this is down to all of us who are in the team," Messi told a radio station in Rosario, the city of his birth.
Argentina face Peru at home and Uruguay away in their last two qualifiers in October, looking to climb into the top four for an automatic World Cup berth or remain fifth for a two-leg playoff with the CONCACAF's fourth-placed team.
Messi also denied reports in Argentine media that he and Maradona did not speak to each other, saying: "The relationship with Diego is great. There are no fights (in the squad), on the contrary.
"When we started with Diego (as coach) we won all the friendlies, we played well. Now it's important to win these two remaining (qualifying) matches."
Brazil and Paraguay have qualified. Chile are third with 27 points, Ecuador have 23 and Argentina 22. Behind them, Uruguay and Venezuela have 21 points and Colombia 20, while Bolivia and Peru are out of the reckoning.
