Roger Federer pulled out of the Paris Masters on Sunday to rest before the ATP World Tour Finals in London.
The top-ranked Swiss announced his move to withdraw from the tournament, which starts Monday, after losing a 2-hour, 44-minute final against Juan Martin del Potro at the Swiss Indoors.
"I'm not going. It's the only right decision for me," Federer said. "I had some niggling stuff and I didn't want to take a chance obviously before the World Tour Finals. I need some time to prepare."
Federer won the Paris trophy last year, and will defend his London title the following week.
"I had one of the best weeks of my life last year," said Federer, who last year's Paris indoor event for the first time at age 30. "The fans were amazing and the last thing I want to do is mislead any fans. This is really just a last-minute decision."
Federer will start a record 302nd week ranked No. 1 on Monday, but risks losing that status to Novak Djokovic in the final two weeks of the season.