BELO HORIZONTE • Lionel Messi has been underwhelming so far at the Copa America, but such is his fearsome reputation that Brazil defender Thiago Silva knows that the Argentina captain "could spring to life" when both sides meet in the semi-finals tomorrow.

At a press conference on Saturday ahead of the first tournament meeting between South American football's two biggest behemoths since the 2007 final, which Brazil won 3-0, the Paris Saint-Germain captain remains wary of the "best player in the world".

He said: "We will have to be especially focused on him when we have the ball and when we don't.

"Sometimes, he can be at walking pace during a game, but he's always looking for space to launch a counter-attack.

"It's a privilege to be able to face him again and we'll have to try and put the brakes on him."

Messi has scored once in the tournament - from the penalty spot - and has admitted he is not playing at his usual level in Brazil.

After recording only three shots - none of them were on target - during Argentina's 2-0 win over Venezuela in the quarter-finals, the Barcelona skipper said: "The truth is I'm not having my best Copa America.

"It's always very difficult for us because we want to do something different and attack, and teams pack the middle of the pitch.

"No one is giving anything away cheaply in this Copa, it's very difficult to play because the pitches are very bad, it's shameful. The ball is like a rabbit, it can go anywhere and you can't dribble."

However, teammate Angel di Maria has defended Messi's lacklustre displays, insisting that he was still "working hard" for the team even if he was not getting on the scoresheet.

The PSG forward added: "We are used to seeing him score goals but Leo is doing very well, he is running a lot.

"He knows more than anyone that at this Copa America, the first thing you need to do is run, then you can think about the rest, playing well and scoring."

REUTERS