Djokovic had earlier wrapped up the year-end No. 1 ranking but his 7-6 (8-6), 7-5 win Monday over Roger Federer really pushed his advantage. He has 12,920 points, which is 2,655 points more than the second-ranked Federer and nearly 5,000 more than No. 3 Andy Murray.
Djokovic racked up his point total over 18 tournaments, which is the lowest total among players in the Top 10. Federer, for example, was in 21 tournaments and Murray 20.
In the last two years Djokovic has a 145-18 record with 16 championships and $22.5 million in winnings. Four of those titles were at Grand Slam events and Djokovic will head into the 2013 Australian Open as a two-time defending champion.
Federer, who was looking for a third consecutive ATP Finals title, also had a strong year, going 71-12 with six titles -- including at Wimbledon -- and $7.4 million in winnings.
Murray has 8,000 rankings points and Rafael Nadal, who missed the second half of the year with an injury, has 6,795 for fourth place. Fifth-ranked David Ferrer has pulled close to Nadal with 6,430 points.
Tomas Berdych had 4,605 points for the No. 6 ranking and Juan Martin del Potro (4,480) is seventh. Jo-Wilfried Tsonga has 3,490 ranking points, which is eighth-most. Janko Tipsarevic is No. 9 at 2,990 and Richard Gasquet (2,515) finishes the year at No. 10.