Fiji centre Seru Rabeni has challenged his team-mates to raise their game they take on South Africa in the World Cup quarter-finals, claiming that the islanders are yet to hit top gear despite their performance against Wales in the Pool B eliminator at the weekend.

Rabeni and his team are the surprise package in the last eight, having beaten Wales on Saturday, to secure second spot in the group.

They were sensational that day but the Leicester star believes there is more to come.

"We haven't played well as a team yet, and we have struggled and scrapped to win games," said Rabeni, a winger for the Tigers but a centre for his national team. "Our attitude now is to improve from the last two games. If we can concentrate and improve things, we can go better."

Fiji sealed narrow victories over Japan and Canada before putting out virtually a second-string team in a heavy 55-12 loss to group winners Australia.

They went up a notch in beating the Welsh 38-34 in the game of the tournament so far, but must go one better if they are to shock South Africa.

The Springboks are second favourites behind New Zealand to win the World Cup and are strong in every department. Rabeni still feels his side have a great chance of making the semi-finals, though, as long as they front up.

"They (South Africa) are only human," he added. "It is 15 versus 15, although it is a continent against an island.

"If we can give them something they can feel, we will make them think about us.

"South Africa's forwards pride themselves on physical confrontation and they are the best in the world at the line-out.

"In the scrum, we can see how dominant they are. We need to get up them, get our own ball and play with it."

Rabeni came off in the second half of the Wales game and has been nursing a sore knee of late but he is confident he will be available for this weekend's encounter in Marseille.

"The knee's going better, there's no more strapping and I'm running freely. I'm not worrying about it."