Novak Djokovic is guaranteed to finish the year as the world's top-ranked tennis player.
Roger Federer's withdrawal from the Paris Masters means Djokovic will regain the No 1 status he lost following this year's Wimbledon.
And defending champion Federer cannot gain enough points at next week's ATP World Tour Finals to overhaul his younger rival.
Djokovic is the first player since Federer in 2007 to finish consecutive seasons in top spot.
The 25-year-old successfully defended in Australian Open championship in January, reached the finals of the French and US Opens and won four ATP World Tour titles.