Novak Djokovic swept aside Roger Federer to claim a historic fourth consecutive ATP Tour Finals title.
The World No.1 beat Federer 6-3, 6-4 to once again end the year as the world's best player.
He is the first player to win the event four years in a row.
The Serbian won a total of nine titles in 2015, including three Grand Slams.
The 28-year-old will now take a break with his family, before gearing up for his Australian Open title defence in January 2016.
“I am looking forward to our two weeks of holiday with my wife and son away from tennis for a bit,” he said.
“Give me some time to recharge my batteries and then I’ll think about next season.”
Djokovic ends the 2015 season with an astonishing 82-6 win/loss record.