Argentina superstar Lionel Messi believes his army of fans will see a different player at the 2014 FIFA World Cup Brazil™ than the one that underperformed for Barcelona in 2013/14.

"As I join up with the national team, the atmosphere is completly different," he said. "Many times in the past when I have gone back to Barcelona, I have played well. Now I am hoping that the opposite happens."

Messi took his time to transcend his talent with Barcelona on to the international stage and it was only after South Africa 2010 that he started to perform well.

When I return to the training ground with my team-mates, with my friends, it's going to change my mentality and it's going to be another story.

Lionel Messi on the prospect on joining the Argentina squad

The 26-year-old returned to his native Rosario on arrival in Argentina, and will join coach Alejandro Sabella and the rest of the squad next Monday at Ezeiza, the team's training camp.

He vowed to train "with maximum energy in order to give his best like always". He added: "When I return to the training ground with my team-mates, with my friends, it's going to change my mentality and it's going to be another story."

He also revealed that along with the rest of the Barcelona team this season, they were suffering from a "lack of energy".

Argentina will play friendlies against Trinidad and Tobago on 4 June and Slovenia three days later.

Their opening Group F match will be against Bosnia-Herzegovina on 16 June, which proceeds games against Iran and Nigeria.