Fiji said their shock victory over Wales and resulting quarter-final spot at their expense was down to sheer hard work, while the Welsh said they had been punished for showing the Pacific islanders too much respect.

Fiji's 38-34 win in a thrilling, see-saw match earned them their first quarter-final since 1987 and knocked Wales out of the tournament. They will face South Africa next weekend for a shot at a semi-final place.

"Years ago Fiji would have lost that game. I'm so proud of the boys," Fiji captain Mosese Rauluni told reporters.

"They stuck to it, and it comes down to all the hard work and the training we did leading into this World Cup. We made it to the quarter-finals, and it was our goal to do that."

He added that close Pool B matches against Japan and Canada had prepared the team well to fight for the full 80 minutes against the Welsh.

"All our wins have been so close, Japan, Canada, those games have helped us to win this game today," he said.

"The fight at the end there, those games helped us a lot and the boys, our defence really stood up to the task."

Fiji coach Ilivasi Tabua said their progress to the knockout stage proved that underdogs were still able to cause upsets.

"It's a great day for rugby as it shows the second tier teams can compete at this level and it will take some time to sink," he said.

"To achieve our goal of reaching the quarter-finals of the World Cup is an amazing feeling."

Wales skipper Gareth Thomas, who scored a try on his 100th test appearance, said his team had made some serious errors and their defence had not been up to scratch.

"Of course this is a failure. We gave Fiji too much respect and too much time on the ball and they punished us for it," he said.

"You have 80 minutes to perform in test rugby, and for 80 minutes we didn't perform -- now we are on the plane home."

Although few people would bet on Fiji similarly upsetting a South Africa side who crushed defending champions England in their pool match, the Pacific islanders said they still had more good rugby left in them.

"We still have something in the tank so I'm sure we can take our game to another level," said centre Seru Rabeni.

Reuters