It means Rafael Nadal needs just one more win - either in Paris or at the season-ending ATP World Tour finals in London - to seal the No 1 spot.



Paris Masters tournament director Guy Forget called Federer's agent Tony Godsick this evening to check on the 19-time Grand Slam champion's plans. It was then when Goldsick officially withdrew Federer from the event, citing a back injury.



Federer beat Juan Martin del Potro 6-7 6-4 6-3 today to lift his record eighth Swiss Indoors title.



Victory ensured he moved to within 1,460 points of Nadal in the ATP rankings but he hinted before the game he wouldn't play in Paris.



Speaking ahead of the Swiss Indoors final, which he won, Roger Federer said: "I'm too far behind really in the points.



"If I thought about it maybe I wouldn't even enjoy the end of the season because the whole season would feel a waste.