Vancouver - United States star Abby Wambach has been vocal in her criticism of artificial turf being used for the first time at football's Women's World Cup in Canada.

But heading into the knockout rounds yesterday, the thorny question that led to a lawsuit ahead of the tournament seems to have lost steam.

"This question about artificial turf, I don't want to hear about it any more," said South Korea's star striker Ji So Yun ahead of today's game against France.

"We just want to focus on our performance now."

Korean coach Yoon Deok Yeo said it was up to the players to adapt to the surface which Fifa president Sepp Blatter has described as "the future of football".

Said Yoon: "Artificial turf has its own characteristics, compared to natural, but we can't blame our results on the turf."

Blatter has claimed that "most countries around the world will play on artificial turf one day because it can be used 24 hours a day, seven days a week".

But being forced to play the top event in women's football on the surface, which had drawn complaints over injury worries and ball bounces, irked the women given that the men's World Cup is played on natural grass.

It sparked the lawsuit against world governing body Fifa which was withdrawn before the tournament got under way.

Wambach rekindled the debate in Canada when she blamed the US' goalless draw with Sweden, their first in seven World Cup appearances, on the surface. "I think that there are a lot more goals in this tournament if it weren't for the turf," she said.

Agreed Aya Miyama, captain of reigning champions Japan: "The natural turf was easier for us. The ball movement could be predicted. In this case, dribbling is difficult."

But the surface did not stop Germany notching up 10 goals against Ivory Coast while Ecuador conceded 17.

"We've demonstrated that you can score so I don't want to make this all about the turf," said German midfielder Melanie Behringer.

Swiss coach Martina Voss-Tecklenburg believes the surface has no impact on the quality of the game.

"It's fine. We just saw a great match between teams playing a high level on this artificial turf and this is what matters," she said after Switzerland's 0-1 loss to Japan.

US coach Jill Ellis added: "The game is different on turf but it's the same for everybody.

"I still think we can make the surfaces play faster by putting water on them."

AFP