A year that began with a 41-match winning streak, included three grand slam titles and saw him knock Rafa Nadal off his perch ended in tame fashion for a "drained" Novak Djokovic when he made an early exit from the ATP World Tour Finals, on Friday.

"You know, my body says that it's overload," Djokovic told reporters before knowing whether or not he would be in action in Saturday's semi-finals.

"It has been too much this year. Obviously, mentally I feel a little bit drained. I just don't have that freshness in my mind for the matches and I don't have these dynamics that I had in all 10 months of the year.

Despite ending the year with his first back-to-back defeats since March 2010, Djokovic said he had been satisfied with his display against Tipsarevic and believed he would be in great shape for the defence of his Australian Open crown.

"If this is my last match in the Masters Cup, I'll be happy because I think, at least compared to the match against Ferrer, I played a little bit better," he said, referring to his 6-3, 6-1 defeat by the Spaniard on Wednesday.

"So I'm sure that if I have as good a preparation as I had last year, I'm confident I can do well in Australia."
Djokovic said he would not be playing any official tournaments until Melbourne.