Hat-trick hero Lionel Messi said it would have been "crazy" if Argentina did not qualify for the World Cup after he guided the two-time champions to next year's tournament.

Outside of the CONMEBOL qualification places and on the brink of elimination, Messi scored three goals as Argentina overcame Ecuador 3-1 in Quito and secured a berth at Russia 2018 on Tuesday.

Occupying sixth position prior to kick-off, Argentina's hopes of at least claiming a play-off spot were dealt a major blow when they conceded after just 38 seconds.

But five-time Ballon d'Or winner Messi saved the day, scoring twice in the first half and again just past the hour-mark to see Argentina – runners-up in 2014 – to their 12th successive World Cup.

"There was always the fear of coming here to play. Luckily, we could react and we managed to play well," Messi told reporters after Argentina finished third.

"We were calm, we achieved the goal and that is the most important thing. Thanks to God, we fulfilled the objective.

"It would have been crazy not to be in the World Cup. The group deserved to qualify.

"There has been criticism despite having played three consecutive finals and today was an important day for all, especially for those who have been here longer."

Messi continued: "We were away from the press for a while and the people. I think it served to get us closer. If we all go hand in hand, everything will be easier.

"It was unfair what happened in the World Cup and the two Copa Americas. We ended up suffering to enter this World Cup and hopefully we will get it once and for all.

"Enjoy the qualification and prepare little by little. The team will change, there will be another and it will grow."