BEIJING (AFP) - Lionel Messi was on Friday tipped to be the driving force behind Argentina's bid for back-to-back Olympic gold after the superstar striker shrugged off a damaging club-or-country controversy.

The 21-year-old scored once and created the second goal in the 2-1 win over Ivory Coast to hammer home his importance to the South Americans who had defied Barcelona's insistence that the player return to club duty in Spain.

"He is the key star here," said Messi's teammate, and Liverpool midfielder, Javier Mascherano.

"He was the reason we won against Ivory Coast. It's very important he is here with us because the games will become more and more difficult."

Messi took the field in Shanghai on Thursday just moments after his Spanish employers had reluctantly given their blessing to his Olympic dream after weeks of wrangling between Barcelona and Argentina.

The Spanish club successfully appealed to the Court of Arbitration for Sport (CAS) to have FIFA's insistence that players be released for the Games overturned arguing that Messi was required for Champions League qualifiers later this month.

Although Barcelona would have been within their rights to block Messi's participation here, Mascherano believes the controversy is now closed.

"Messi will play the whole tournament," added the Liverpool star.

Messi refused to discuss the controversy but admitted that he was overjoyed with his performance at the end of a trying week.

"It was my first goal in the Olympic Games and that was very important," he said.

"I played well with Juan Riquelme. But we are not the dream team until we make the final."

Coach Sergio Batista was delighted that his long-running battle to keep Messi in China had paid such rich dividends.

"Messi had a fast pace and was in great form," said the coach.

"He is a fantastic player. He had great pace and performed so well which gave great confidence to the whole team.

"After so many troubles, all the efforts paid off."

But Batista was keen not to ignore the contribution of playmaker and skipper Juan Riquelme who was at the heart of most of Argentina's more promising moves.

"He's in great form. He is just like an engine in midfield and offered so much assistance to Messi."