The 19-year-old Dane with Polish parentage climbed to fourth in the world rankings on the eve of the Tour Championships in the oil-rich state of Qatar -- proof that as well as being a new calendar girl for the women's Tour she can back it up on court.

After collecting titles in Ponte Vedre Beach, Eastbourne and New Haven, Wozniacki stunned New York, ousting new American darling Melanie Oudin on her way to the US Open final where she was beaten by comeback mum Kim Clijsters.

The one cloud on the sky blue horizon for Wozniacki came in Luxembourg last week when she picked up a muscle injury in the second set of her match against local girl Anne Kremer and retired while leading 7-5, 5-0 knowing that she would not be able to play in the next round.

A gesture of goodwill to her opponent ended up with her conduct being investigated by the WTA after some lucky gamblers overheard her on-court conversation with father and coach Piotr and made a killing from her decision to withdraw.

The incident, that overshadowed her arrival in Doha, is unlikely to be held against a player who has played an astonishing 87 matches on Tour this year but it did prove that life in the fast lane can have its unexpected pitfalls.

“I mean, I didn't do anything wrong. I was injured,” Wozniacki said.  “There was no chance for me to finish. So I decided to stop. I don't have anything to do with betting. I don't do betting. I'm against it. So I don't see any problems.”