Season is ended for me

World number one Serena Williams has announced her withdrawal from next week's China Open in Beijing and the WTA Finals in Singapore, ending her season.

“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 21-time Grand Slam winner said in a statement.

The China Open first tweeted the announcement, but the Women's Tennis Association has not confirmed Williams’ withdrawal from Singapore's year finale.

The American's announcement comes a day after world number three Maria Sharapova also pulled out of the China Open with a left forearm injury.

Williams, 34, has not played since she lost in the semi finals of the US Open to Italy's Roberta Vinci, one of the most shocking upsets in recent tennis history.

“It's no secret I’ve played injured most of the year -- whether it was my elbow, my knee, or, in the finals moments after a certain match in Flushing, my heart," Williams said, referring to her US Open defeat.

Williams’ coach Patrick Mouratoglou told ESPN earlier this week that she was intensely disappointed after missing out on a fifth consecutive Grand Slam crown and hinted that she may withdraw from the remaining tournaments of the season.

Even missing out of the two final tournaments of the year, Williams will still end the year as world number one. “I'm really sorry for Serena. But Serena is Serena. (She is) still a great player also if she doesn’t play,” Vinci said in response to Williams' withdrawal.

Williams has won 21 career Grand Slam titles, one shy of Steffi Graf's Open Era record and three off the all-time record set by Australian Margaret Court.

“I don't doubt she will have the motivation to win more Grand Slams and reach records,” Mouratoglou said. "I'm just thinking about the end of the season, and I don’t know how high the motivation is, and I don't think she should go play competitions if her motivation is not high enough.

“It's not time to doubt whether age will affect her,” he said. “She has a lot of time left.”