LONDON (AFP) - World number three Andy Murray was forced to withdraw from the ATP World Tour finals here on Tuesday after failing to recover from a groin injury. Murray was told he would need up to 10 days off after suffering the injury in practice last week and, although he initially ignored that advice to play David Ferrer in his opening match at the O2 Arena, he has now decided to pull out of the season finale less than 24 hours before he was due to face Tomas Berdych. Murray, who will be replaced by Serbian Janko Tipsarevic, knew he was in trouble during Sunday's defeat.