Serena Williams has pulled out of next week's Kremlin Cup in Moscow due to an ankle injury, the women's tennis body WTA said on Friday.
The US Open champion Williams will not step onto the court again until the season-ending Masters in Doha starting in late October, according to the WTA at the Porsche Grand Prix in Germany, reported dpa.
Williams crashed out in Stuttgart in her first match against China's Li Na on Wednesday and as a result lost the world number one position to Jelena Jankovic of Serbia.