Montevideo  - Lionel Messi did not exactly look happy when he was substituted 10 minutes from time in Argentina's match against Uruguay late Wednesday.

Still, the Barcelona striker remains a key element in coach Diego Maradona's plans for the 2010 World Cup in South Africa, where he is likely to get yet another chance to settle his undoubted debt with the national team.

Maradona did not immediately confirm whether he was to remain at the helm of the national team.

However, following the key 1-0 win against Uruguay in Montevideo he said his squad in South Africa will feature Javier Mascherano, Messi, Martin Palermo and Jonas Gutierrez. He did not mention any others by name.

"We will always wait for (Messi). It is the great challenge," the coach said in recent days.

At the time, Maradona defined him as an ace. But he then pulled him off the pitch. Messi did not appear to like the decision, and he left the pitch with his head down amid whistling from the fans. Once again, he had failed to perform.

Messi is an unknown, a pending debt, an indecipherable enigma for Argentine fans, who can still not understand the variations in the performances of a football superstar depending on the shirt he is wearing: Fantastic for Barcelona, a continuous disappointment for Argentina.

It is true that he cannot play alone against the world and that many of his team-mates have also played badly in the qualifiers. But it is also certain by now that he does not have the football courage required to take charge of the national team, as many expected from the heir to Maradona's number 10 shirt.

In the 2006 World Cup in Germany, coach Jose Pekerman tried to shelter him from public scrutiny. Now, at age 22, Messi is all set to take the Ballon d'Or and the FIFA World Player of the Year award. He won a historic treble last year with Barcelona, and he recently extended a most lucrative contract with the La Liga giants.

For Argentina, however, he has never shone.

As so many times before, some expected Messi to be extra motivated to fight criticism, and particularly so when faced with the risk of missing the World Cup altogether. But they were wrong once again.

Maradona stressed the need to instil in Argentine players the value of the blue-and-white shirt they wear.

"I think that now, when we have more time, we can get more things into the boys' heads about what this shirt means, about what it is to touch on the ball, about what a footballer's quality is, about the prestige that the national team gets from winning a match," he said.

"We have a responsibility for wearing a historic shirt like Argentina's," he stressed.

Maradona mentioned midfielder Mario Bolatti - the hero against Uruguay after scoring the lone goal of the game - as a role model.

"You've got to love the 'Gringo:' he has manners, he works hard, he never fails you, he does what you ask him to do, and on top of that he scores a goal," the coach said.

"When he did not get to play he took it like a gentleman, helping his team-mates. And that is a plus for the World Cup's 23 (men squad)," Maradona said.

Argentina are now set to play in South Africa 2010, but they still have plenty of work to do. They'll need to find a solid, reliable team, they'll need to practice and develop a strategy that allows a global football giant to get back lost prestige.

And Maradona will have to keep trying to get Messi to the top level that made him arguably the world's best player.  dpa