Attack coach Nigel Davies admits Wales cannot afford to make any silly errors against Fiji in Nantes if they are to be sure of staying in the World Cup.

Wales go head-to-head with Fiji on Saturday for a place in the quarter-finals and the right to play South Africa in Marseille. The losers are on the next flight out of France.

Wales head into the game as favourites, but the Fijians bring with them a sense of the unknown and a lethal ability to capitalise on turnover ball.

Fiji proved that in their victory over Canada at the Millennium Stadium last weekend when they sealed the match with a 95-metre breakaway try from full-back Kameli Ratuvu with the final play of the game.

Wales are anxious to play their own brand of attacking rugby, but Davies concedes they may have to tone down that ambition to ensure Fiji cannot catch them on the break.

"They are a huge threat to any team,'' said Davies. "Their outside centre, wings and full-back are capable of breaking any team in the world - and that is where their main threat comes from.

"They are a side that plays its best in a loose game environment, and they attack from from turnovers and where the opportunity arises.

"Some tries this World Cup have been fabulous - but they have been as a result of teams making mistakes against them and being punished as a result.

"We don't want to take anything away from ourselves but we have to balance it with an ability at the set piece to maybe take something away from them.'' The set piece is a major concern for Fiji captain Mosese Rauluni, after Australia dominated the scrum and line-out as they cantered to a 55-12 victory on Sunday.

"Against Australia we lost our ball at the set piece, got pushed off our scrum. It is a big thing to lose,'' he said. "It was very frustrating, very disappointing - and it just adds to the pressure.

"We hope to put it right for Wales, because they played well against Japan.'' Wales captain Gareth Thomas returned to contact training yesterday and seems set to be involved against Fiji.