World number one Djokovic ended a superb season by beating Roger Federer on Sunday to claim a record fourth straight ATP World Tour Finals title.
The Serb won 6-3 6-4 in 80 minutes at London's O2 Arena, making amends for his loss to six-time champion Federer in the group stage of the season-ending tournament.
"I am enjoying every moment on the court, I cherish every moment after dreaming of it as a kid," Djokovic said after his win.
The 28-year-old ends 2015 with 11 titles, including three Grand Slams.
Federer, meanwhile, ends 2015 as the world number three, with his failure to win the final meaning Murray ends the year as world number two for the first time.
"It is never fun on the not winning side, but it is better than not playing at all like last year," Federer said on Sunday night.
"This week was great, there were some crazy points tonight, but like plenty of times this year Novak deserved it."