Ghana coach Ratomir Dujkovic has warned his team not to be duped by Ronaldo's size.

The Brazil striker's weight has made as many headlines as his play in Germany but after his double strike against Japan last week, Ronaldo is just one short of eclipsing Gerd Muller as the most prolific goalscorer in World Cup history.

And, while Dujkovic is desperate to ensure Ronaldo does not achieve his landmark 15th goal against the Black Stars in Dortmund, he recognises the 29-year-old's star quality.

"Ronaldo is a great striker," said Dujkovic.

"His weight has nothing to do with his ability to score goals.

"He is an important figure for Brazil. He is always dangerous and we have to be aware of that."

Although Ghana are without suspended Chelsea midfielder Michael Essien, Dujkovic is bullish about their chances of winning their historic first meeting with Brazil and joining a select band of African nations who have made the quarter-finals.

"I am confident we can get a result," said Dujkovic, who has been tipped to return to his native Serbia after the tournament to take charge of the national side, who performed so abysmally at Germany 2006.

"Team spirit and collectiveness are more important to us than any individual and although we recognise the game will be extremely tough for us, I still believe we will reach the semi-finals.

"The thing we must not do is be intimidated by those yellow shirts.

"My players cannot afford to be standing on the pitch looking at their idols and wondering how they are playing. They have to try to stop them."

As one of the players who must actually go out and win the game, key midfielder Sulley Muntari was understandably more cautious in his assessment of the challenge which awaits.

However, after Essien kept a promise to his room-mate to guide Ghana into the knockout phase when Muntari was banned for the final, decisive encounter with the United States, the 21-year-old, seemingly Premiership-bound once the tournament is over, feels an overwhelming obligation to return the favour.

"Michael promised me he would get us through against the United States, so I have promised him we will do the job for him," said Muntari.

"Nothing is impossible. Brazil have world-class players, we all know that. But football is a game of chance. On any given day, anyone can be beaten."