PARIS (Reuters) - England flyhalf Jonny Wilkinson faces a fitness battle before the world champions' key Pool A match against South Africa on September 14 after an ankle injury was confirmed as a ligament sprain.

Wilkinson was ruled out of the opening match against the United States in Lens tomorrow after injuring his ankle in training.

He underwent an X-ray and scan on Tuesday and the results showed he had sprained a ligament.

Wilkinson has represented his country only seven times because of a series of injuries since drop-kicking the winning goal in the 2003 World Cup final.