Serena Williams cites nagging injuries in pulling out of lucrative WTA Finals

World No 1 Serena Williams opted against defending the WTA Finals tennis title and decided to end her season early following a roller-coaster campaign littered with both pain and prizes, the American said yesterday.

The 34-year-old's last match was her shock loss to Italy's Roberta Vinci in the semi-finals of the US Open last month, which ended her bid to become the first woman in 27 years to win all four grand slam titles in the same season.

The 21-time grand slam singles champion said she had been carrying injuries throughout the campaign and the loss to Vinci had taken its toll, adding she would not play again this year after also pulling out of next week's China Open.

"My journey in tennis this year has been at times exhilarating, at times disappointing," Williams said in a statement carried by China Open organisers.

"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 [Meadows], my heart.