Top seed Novak Djokovic on Friday pulled out of the ATP Paris Masters, in which he was due to play Frenchman Jo-Wilfried Tsonga in the quarterfinals, because of a shoulder injury.
The Serb world number one said his shoulder had worsened after his 4-6, 6-3, 6-1 victory over compatriot Viktor Troicki on Thursday.
"Sadly I have to inform you that I have withdrawn from the further tournament," Djokovic announced on his official website.
"I have pushed myself to the limit by playing, and after the match yesterday my shoulder got worse.
"For this reason, I have to put my health first and withdraw even though my urges as a professional player are making me want to play until the last drop of energy.
"I am very sorry for all of you who bought tickets and wanted to come and watch me play. My season has been long and tiring, I played all of my matches at my highest level, and now my body is aching for recovery. Hoping for your understanding and support."
Djokovic, who has notched up 10 titles this year including successes at the Australian Open, Wimbledon and the US Open, on Wednesday laughed off suggestions that he only turned up for the Paris Masters in order to avoid missing out on a $1.6 million windfall.
Djokovic's participation was cast into doubt by his shoulder injury and, having already pulled out of last month's Shanghai Masters, another withdrawal would have cost him his lucrative share of the ATP bonus pool.
"If I know that I'm physically good enough to be competing, I will compete. If I don't, I will not compete," he said at the time.