Andy Murray spent two hours debating whether to play on at the ATP World Tour Finals, and concluded that his body had made the decision for him.
The third-ranked Briton pulled out of the season-ending tournament yesterday with a groin strain he sustained in training a week before his opening match.
After struggling through a straight-sets loss to David Ferrer, Murray decided to take the safe option after conversations with his support group.
"I was just trying to find reasons why I should try to play," Murray said. "But, you know, there was no real positives [to] coming out and playing because yesterday I was really unhappy on the court. I wasn't enjoying it at all.
"This is one of the best tournaments in the year, one that I think me and all of the players look forward to playing. I couldn't give anywhere near my best."
Murray said the injury wouldn't require surgery but that he feared it might get worse if he carried on playing. His main concern was not disrupting his preparation for the Australian Open in January, the first Grand Slam of the new season.
"The Australian Open is six, seven weeks away," Murray said. "I could mess up my preparation for that.
"That off-season is so important for me, and has been for the last few years of getting myself in shape."
Murray will be replaced in the round-robin tournament by reserve player Janko Tipsarevic, who will play Tomas Berdych. Tipsarevic will start with a 0-0 record.
Murray's withdrawal will keep concerns over the busy men's calendar in the spotlight.
He is not the only player to have arrived in London hurt. Rafael Nadal said after his loss to Roger Federer he had a shoulder problem, Mardy Fish is nursing a hamstring injury, while Novak Djokovic also has an injured shoulder, putting a dampener on an event billed as the "final showdown" between the year's top eight players.
- AP