Roddick's World Finals place at risk after knee injury

The pain in his left knee dominated his thoughts here last night, but as Andy Roddick heads for home after his retirement from the Shanghai Masters he might consider that his scathing criticisms of the gruelling tennis calendar were perfectly timed.

Roddick, who had warned 24 hours earlier that the health of the leading players was being put at risk, was leading 4-3 when he hurt his knee against Stanislas Wawrinka and was unable to continue. Roddick said that it was not yet clear how much damage he had done or what the implications would be for the remainder of his season.

The injury could scupper his chances of qualifying for next month's Barclays ATP World Tour Finals in London. Five players (Roger Federer, Rafael Nadal, Andy Murray, Novak Djokovic and Juan Martin del Potro) have already secured their places in the eight-man field, with results here and in the final Masters event in Paris crucial to the chances of those hoping to join them.

Roddick was the best placed contender and his injury will improve the chances of Jo-Wilfried Tsonga, Nikolay Davydenko and Fernando Verdasco, who are immediately behind him in the rankings, which will determine the line-up.

Lleyton Hewitt, a 6-2, 6-4 winner yesterday over John Isner, has too much ground to make up, but after climbing 85 places to No 23 in the rankings in the last eight months is optimistic about the future. He still feels he has another major title in him and is looking forward to "doing some damage" at his home Grand Slam tournament in Australia in January.