Carlos Bilardo has warned opponents that the only way to stop Albiceleste captain Lionel Messi is to foul him.
The 73-year-old coached Argentina to World Cup success in 1986 on home soil and is now general manager of the national side.
The Barcelona star has been in great form for both club and country so far this term, most recently scoring twice against fierce rivals Real Madrid.
"You have to see him in training and see him really take off," Bilardo told AS.
"He goes from 0-50 km/h in a second. The only way to stop him is to kick him. If you don't, you can't stop him.
"For him, the ball is like an extra bone in his body, and he runs with the ball as if he didn't even have it with him.
"Once he gets going, forget it, you won't catch him. You have to follow his footsteps before then because he'll beat you by 10 metres.
"He has unbelievable pace. He's at his best in the final third, he's unstoppable in that area of the pitch."
Bilardo also spoke about his nation's chances in the 2014 World Cup and believes they are capable of winning the tournament - if their star man is on form.
"If Messi is in good shape and if there's another great player in the team, Argentina will be able to do great things in the World Cup," he added.
"But first of all they have to qualify. The other day [against Uruguay] he played very well with [Sergio] Aguero and [Angel] Di Maria.
"They play excellent one-touch football, sometimes it looks as though they're going to lose the ball, but they always get there with their toe, and keep hold of the ball," he added.