PORT HARCOURT, July 28 -- FIFA has issued a warning to Ghana not to under-perform against Nigeria here on Sunday in a match that will determine Africa's final qualifier for next year's World Cup, Ghana's coach said Saturday. A draw or a victory for Ghana in this southern city will stop Nigeria from qualifying for the World Cup while paving the way for Liberia to feature in their first-ever soccer finals appearance.

Liberia, inspired by former world footballer of the year George Weah, top Group B with 15 points from eight matches but a win for the Super Eagles Sunday will guarantee the experienced Nigerians their third consecutive appearance at the World Cup.

"FIFA has told the GFA (Ghana Football Association) in very clear terms that we should play our best against Nigeria so that only the best team will represent Africa," Fred Osam-Dudu told AFP at the team's Rachael Hotel on Aggrey Road. "We're here to create an upset. The local players along with (Mohammed) Gargo will do the job for me," the coach added.

Ghana's three Europe-based professionals, Charles Amoah, Emmanuel Duah and Stephen Appiah, are still being expected for Sunday's World Cup tie against Nigeria.

"We are still waiting for them but even if they don't show up we are ready to match Nigeria power for power, skill for skill," said Mohammed Gargo, the only overseas pro here.

Weah has also cautioned against any underhand deals between the two West African countries.

The rumour here is that Weah was in Ghana this week to give the Black Stars "super motivation" not to lose to 'Old Enemy' Nigeria.