World number one tennis star Serena Williams has withdrawn from the WTA Finals in Singapore in order to 'address her health' and allow time to "heal".
The 34-year-old American, who has 21 Grand Slam titles to her name, has also pulled out of the upcoming China Open.
Williams won three major titles this season - the Australian Open, the French Open and Wimbledon - but she fell short of completing a calendar Grand Slam after getting knocked out of the US Open by Roberta Vinci in the semi-finals.
A statement from Williams read: "It's no secret I've played injured most of the year, whether it was my elbow, my knee, or, in the final moments after a certain match in Flushing, my heart.
"I'm a fierce competitor and I want to compete as well as I can, for as long as I can. So I am taking a proactive step and withdrawing from tournaments in Beijing and Singapore to properly address my health and take the time to heal."
The WTA Finals get underway in Singapore on October 25.
