Lionel Messi was taken by surprise during Argentina's training session on Wednesday by a pitch invader he briefly mistook for his former Barcelona team-mate and friend Ronaldinho.

Argentina trained in front of thousands of fans and press at Belo Horizonte's Estadio Independencia, where Ronaldinho regularly turns out for Atletico Mineiro.

After some light running, the Albiceleste squad were divided into small groups for games of football-tennis in a low-key session which finished amid chaos as over a dozen supporters climbed over the fences to invade the pitch and ran in search of a handshake or a hug from their heroes.

Most headed in Messi's direction and security guards were overwhelmed in their attempts to halt the fans as the practice was quickly brought to an abrupt end.

But the Argentine was initially fooled by the Ronaldinho double.

Robinson Oliveira, who works as a professional lookalike of the Brazilian forward, told Goal: "When he saw me he was shocked because he thought I was the real Ronaldinho and he told me that I didn't need to run on the pitch to see him.

"He said: 'What are you doing running on here to see me?' When he held my hand, I went down on my knees [and bowed]. It was so emotional."

He added: "I didn't plan this. I just thought to myself that I have to hold his hand because this is the only opportunity I will have to see him."

The lookalike, who bears an uncanny resemblance to the former Barca hero, ended up with a bloodied hand after scaling the fence in his adventure to meet Messi, but said: "It was worth it."

Asked which of the two players he prefers, he replied: "Ronaldinho, of course!"

Argentina and Messi kick off their World Cup campaign against Bosnia at the Maracana on Sunday.