Lionel Messi could not be happier than at Barcelona, and can crown his status as an all time great by winning the World Cup with Argentina, national coach Edgardo Bauza told AFP on Wednesday.

"I can see just how happy he is at Barcelona with his family around him," said Bauza, who has been at the helm of the Argentine national team since August 2016.

"Of course when Leo is happy that helps him give his best performance, morale is crucial for form," said the 59-year-old former defender.

"A footballer is happy when he is playing and winning, otherwise he is rarely happy," said Bauza.

Messi's Barcelona were beaten 4-0 at Paris Saint-Germain last week in their first-leg last-16 Champions League tie and with his contract running out in 2018 there is speculation he may leave.

The coach refused to be drawn on Messi's future.

"At Barcelona, Manchester City or wherever, that's his decision to take. I just want him to play and that's all."

"He's the type of player who always wants to be on the pitch, never wants a rest."

The coach went on to say Messi's international record, with the trophy cabinet with Argentina bare, was no stain on his achievements.

"Some say the fact he's won nothing with Argentina means he's not the best in the world, not the most dangerous, not worth as mush as some others," said Bauza.

"But we are going to try and win this next World Cup, which will make him one of the greatest of all time."

Argentina are currently fifth in the qualifiers for the South American 2018 World Cup qualifying group with four games to go.