Both sides need the points in the Group B game in Bloemfontein after losing their opening matches, but Nigeria showed flashes of form in the 1-0 defeat by Argentina while Greek defensive errors handed South Korea a 2-0 victory.
"In the first match we didn't do what we could. Why, I don't know," midfielder Sotiris Ninis told a news conference.
"Tomorrow is our last chance, there will be no other chance to catch up with losses. Either we will win or that will be the end and we will have to return to Greece disappointed."
In fact, three points could be enough as the U.S. proved last year in losing their opening two games in the Confederations Cup but still progressed to the final in South Africa before losing to Brazil.
Greece not only failed to win a match in their only other finals appearance in 1994, they did not even manage to put the ball in their opponents' net.
German coach Otto Rehhagel, who led them to an unlikely European Championship win in 2004, has been criticised for his defensive approach but he denied this limited their ambitions.
"We have played always in our way, we have been successful. When I and my assistant started, Greece were in 65th place and we have advanced since (to 13th). If one day we have Ronaldo, Kaka and Messi in our team, then we can certainly play this kind of football."
MUST GIVE EVERYTHING
Veteran striker Fanis Gekas also dismissed the idea that Greece's reliance on defence held back the search for goals.
"I don't think our tactics focus too much on defence, during the preparation we scored quite a few goals.
"Of course we want to protect our goal but I really don't believe we play too much on the defensive side," said Gekas, who was the top European scorer in the qualifiers with 10 goals.
Coach and players made no excuses for the defeat by South Korea.
"There where some individual and unnecessary mistakes. Tomorrow our team must show it still has an opportunity and it must fight for it with passion," Rehhagel said.
All the players were fit, he added.
"I think we can use our full potential and will present a team that must be ready to give everything for Greece and for themselves," he said.
Greece will face Argentina, one of the tournament favourites, in their final group match.
All four of Nigeria's World Cup wins have been against European opposition - including a 2-0 win over Greece in 1994.
