World No.1 out of China Open and WTA finals

That's because Williams announced that she is withdrawing from next week's China Open and the forthcoming event in Singapore in a bid to allow her body to recover from a grueling season.

The 34-year-old hasn't played since suffering a shock defeat to Roberta Vinci at the semifinal stage of the U.S. Open last month.

"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," Williams told the China Open website.

"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.

"This is a very difficult decision but one ultimately made because of the love of the game.

"I plan to return to practicing and participating in exhibition matches later this year. And when I do, l will focus and focus and focus so I can continue my journey in this beautiful game."

Williams enjoyed a stellar 2015 -- winning the Australian Open, French Open and Wimbledon to take her grand slam tally to 21.

She lost just three matches out of 56 with the latest of those against Italy's Vinci.

The U.S. star is just behind Steffi Graf, who holds the record for the most grand slams in the Open era.

Williams, who won the end of season finals in Singapore last year, will now concentrate on recuperating ahead of the new season.

It means that there will be another spot up for grabs with the competition usually including the top eight female players on the planet.

(CNN)