[Rusty Backhand]

NEW YORK, Sept 9 (Reuters) - Russian teenager Maria Sharapova said she was exhausted by her fight-back to force a third set in her loss to Kim Clijsters in Friday's U.S. Open semifinals and must improve her physical conditioning to reach her tennis peak.

http://go.reuters.co.uk/newsArticle.jhtml?type=tennisNews&storyID=9614998&section=news&src=rss/uk/tennisNews