Serena Williams has withdrawn from next week's Pan Pacific Open in Tokyo, citing fatigue after a busy summer schedule.
Williams won titles in 2000 and '02 in her only two appearances in Tokyo. She has played in Asia only once since 2005.
"I'm disappointed to have to withdraw from the Pan Pacific Open, which I was very much looking forward to playing this year," Williams said. "Unfortunately, with the number of matches I have played throughout the summer, I need more time to properly recover."
Since losing in the fourth round of Wimbledon, Williams has played 22 matches across four tournaments. Her heaviest summer schedule ever culminated with a U.S. Open title two weeks ago. With a month and a half remaining in the season, Williams has already played 71 matches this year (67-4), surpassing her previous career high of 62 from 2012. Williams would have had little to play for in Asia. She's already qualified for the year-end WTA Championships in Istanbul, and she's in prime position to lock up the year-end No. 1 ranking. Williams has a 2,755-point lead on No. 2 Victoria Azarenka and is defending 1,500 points through the end of the season compared to her rival's 2,035 points.