Wrist injury threatens Clijsters' Open defence

The world number two, who battled back from a career-threatening wrist injury last year, retired while leading Canadian wildcard Stephanie Dubois 6-1, 2-3 in her second-round match on Wednesday.

"I'm going to have an MRI done Thursday and see what the doctors say," top-seeded Clijsters told reporters.

"I

Clijsters, the defending champion in Montreal, called for the trainer when she was leading the second set 2-1 but when she fell in game six she decided to retire from the match.

"It was hurting and then I slipped and landed on it in the worst possible position," said the 23-year-old.

The U.S. Open starts in New York on Aug. 28.