Federer, meanwhile, defied those who believe that having celebrated his 30th birthday this year, his best was behind him.
The Swiss won his first title in Doha in January before picking up three more in the home straight in Basel, Paris and a sixth World Tour finals trophy.
In between, he had suffered his first ever Grand Slam loss after being two sets up when Jo-Wilfried Tsonga stunned him in the Wimbledon quarter-finals.
He had previously boasted a 178-0 Grand Slam win-loss record when winning the first two sets.
That record was further blemished by Djokovic at the US Open.
However, his World Tour Finals win in London means Federer, who finished the season without a Grand Slam title for the first time since 2002, will go into the new campaign on the back of a 17-match winning run.
“For me, it was the strongest finish I’ve ever had in my career. I’m looking forward to next year,” he said.