Messi is on fire in his last World Cup year! Watch him for PSG LIVE on beIN SPORTS | Foxtel, Kayo, Fetch & beIN SPORTS CONNECT
The mercurial Paris Saint-Germain forward will attempt to lift the trophy for the first time after helping his country win the Copa America last year.
Messi, 35, says he will not play in another World Cup after the showpiece in Qatar, which starts on 20 November.
"This is my last World Cup, surely, yes," Messi said.
The seven-time Ballon d'Or winner does not believe Argentina go into the tournament as the favourite to be crowned champion.
"We are not the top favourites. I think there are other teams that are above us today.
"We arrived at a good moment because of how things turned out and with a very strong group. Afterwards, in a World Cup anything can happen, it's very difficult. The favourites are not always the ones who end up winning.
"I see similar things from the group with the one from 2014. We can't wait to get together."
The 2014 World Cup was the closest Messi has come to winning the tournament, with Argentina beaten by Germany in the final.