Beaten finalists four years ago in Brazil, Argentina struggled in the qualifiers, only securing their ticket with a win in their final match, but they were far too strong for a Haiti side 103 places below them in the Federation Internationale de Football Association rankings.
Messi, who took his global tally to 64 goals, also setup Sergio Aguero for the final goal of the night.
Messi's first-half opener came from the penalty spot after 17 minutes, then he scored twice after the break before creating the goal for Aguero, who has recovered from a knee injury, at Boca Junior's stadium in Buenos Aires.
Argentina and Peru kick-started their final preparations for the 2018 FIFA World Cup Russia™ with morale-boosting home wins on Tuesday, while Panama had to settle for a scoreless draw against the visiting Northern Ireland.
It was a convincing - if not surprising - win for a team ranked fifth in the world, 103 places above their opponents.
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Remarkably, it took Watson 11 balls to get off the mark, but after that he belted 11 fours and eight sixes in the monster knock. The veteran off-spinner didn't get a chance to bowl in the previous match and was sidelined for the crucial final .
"I played and scored against Croatia once, in 2011 at U20 World Cup and we won 5-2".
"We felt the affection of all the supporters tonight, unlike at other times [when there have been insults]".
"The World Cup is our dream, the dream of the country".
"No one should doubt that we're going to give our all, as our supporters demand".
Messi insists winning it with Argentina would be particularly special and says he doesn't regret not swapping allegiances to Spain, despite their win in 2010. "This is a lovely opportunity and we're going to give it our all".
Argentina kick off their World Cup campaign against Iceland on June 16.