"I'm a bit tired. We weren't expecting to play two hours and 30 minutes just before the start of the season," said Djokovic who is aiming for a possible seventh Australian Open title next month.
The Wimbledon and US Open champion sets his eyes on Qatar Open that starts on Monday where he will take on Bosnia's Damir Dzumhur in his tournament opener.
Djokovic had a fruitful year as he made a remarkable comeback into the tennis arena by winning two Grand Slams -- the Wimbledon and the US Open.
Djokovic defeated Kevin Anderson in the Wimbledon final by 6-2, 6-2, 7-6 in straight sets to clinch his fifth title at the All England Lawn Tennis and Croquet Club.
In the year's final Grand Slam in New York, the Serbian defeated Argentine Juan Martin del Potro 6-3, 7-6 (7-4) 6-3 in an exciting final winning his third US Open title.
The Serbian sits on the third position in the Grand Slams tally winning 14.
Spaniard Rafael Nadal has 17 Grand Slam titles whereas Swiss legend Roger Federer tops the chart with 20 Grand Slams.