Argentina's Lionel Messi has singled out Spain as the team to avoid at the 2018 World Cup.

La Albiceleste only narrowly clinched a spot at next year's tournament during the final round of CONEMBOL qualifying, beating Ecuador 3-1 while Peru and Colombia drew 1-1.

It was a little too close for comfort, particularly when Ecuador initially went 1-0 up in that match, before a Messi hat-trick blew them away.

Jorge Sampaoli's side will need to improve significantly if they are to have a similar impact to the 2014 edition, when they lost to Germany after extra-time in the final.

And Messi conceded that Argentina are probably not among the main favourites this time.

He told ESPN: "Spain, Brazil, Germany and France are the teams with the best image at the moment. I think they are the favourites.

"I would not like to face Spain in the group. I would prefer to avoid them because of what their team represents, for what they have [in terms of talent]. They'd be a very difficult opponent."

Messi, though, is not giving up on his dream of World Cup success, vowing to complete a 65-kilometre pilgrimage from his hometown Rosario to San Nicolas on foot.

"If we win the World Cup, I promise to walk from Rosario to San Nicolas," he said to TyC Sports.

And with Argentina no longer having to worry about whether or not they will be participating in Russia, Messi is free to admit the team almost went "crazy" as they struggled to book passage to the finals.

"I thought we were going to [qualify] before," he said. "I thought that we would win against Venezuela and Peru.

"We could not fail to qualify for the World Cup. When Ecuador scored the goal, a lot of things happened to me, but we were lucky not to go crazy."