Otto Rehhagel, at 71 the oldest coach at the World Cup in South Africa, is not ready to return home just yet.

The German is determined to drive Greece to victory over Nigeria on Thursday and rekindle their hopes of progressing from Group B.

A 2-0 defeat by South Korea in the first match continued the Euro 2004 winners' dismal World Cup record.

Greece have lost all four games they have played in the finals. They have failed to score and have conceded 12 goals.

Yet Rehhagel, who led the nation to unexpected glory at the European Championships six years ago, is convinced they can turn things around.

"We still have an opportunity and can recover after losing the first game," said Rehhagel, whose side clinched a place among the elite with a dramatic play-off victory against Ukraine.

"First of all we have to keep our mistakes to a minimum. We have to play to our full potential and give everything.

"Of course we want to score goals. But I do not think we are that defensive. Perhaps if we had (Lionel) Messi, Kaka and (Cristiano) Ronaldo our style would be different."

Bloemfontein is experiencing a cold snap, with freezing conditions expected at the Free State Stadium for the match - and that is welcome news for Rehhagel.

"I think it is better for the players to play in the cold, rather than hot conditions, " he added. "But we cannot use the weather as an excuse."

Georgios Samaras admits they need to regain their defensive pride - or face the consequences.

The Celtic striker was alarmed at the way the team fell apart in the defeat by South Korea.

"We made too many stupid mistakes," he said. "We did not defend at all well, which is usually our main strength.

"Nigeria is a tough test for us. They have many talented and strong players playing in top leagues. It will be a chance for us to get back to what we do best, which is frustrating the opponent.

"If a player makes a mistake, the man closest to him needs to immediately react and work twice as hard to solve the problem.

"If we lose, our World Cup is over. It is the same for Nigeria (after losing their opener 1-0 to Argentina).

"We just need to play better football."

Nigeria coach Lars Lagerback says he is "positive" going into the crucial Group B.

Even though his side lost to Argentina in the opening match, the former Sweden boss took a lot out of the game.

He is not contemplating defeat against the Greeks, who also went down in their opening fixture with South Korea.

Lagerback said: "I am feeling positive. This a big challenge and probably a match we must win if we are not to go home.

"We have had a good week. I have been impressed with the players' attitude and the way they have trained.

"We need to start winning of course and that would make me very happy. To do that, our priority is to be a little bit sharper."

Lagerback has a short-term contract until the end of the World Cup and added: "I do not what will happen later as we have not talked about that."

He expects a tough match against Greece, who reached South Africa after beating Ukraine in a play-off.

Lagerback said: "There are small margins between some teams and Greece have some good players."