Not perfect 'healthwise,' says Novak Djokovic after lackluster final

WATCH—Prakash Amritraj recaps the ATP Finals from London:

Novak Djokovic says he has not been at his best physically since before the Paris Masters.

The world No. 1 was dominant in first four matches at the ATP Finals in London, but had a letdown during the final against Alexander Zverev, falling in straight sets. He also reached the final of the Paris Masters two weeks before, falling to Karen Khachanov in what appeared to be another tired performance following tough semifinal and quarterfinal wins.

The Serb agreed with the suggestion that his success during the second half of the season could have depleted him.

"Health-wise I haven't been really perfect in three, four weeks," he said. "But at the same time I played finals of Bercy and here. I mean, I have to be happy with that result. Of course, finishing the year as No. 1, that was the goal coming into the indoor season. I managed to achieve that.

"Overall it was a phenomenal season that I have to be definitely very proud of."

Djokovic did not specify what the problem was, but had mentioned that his illness was the same he had experienced during Paris.

"It is. Unfortunately today hasn't been great in terms of that," he said following his round-robin victory against Zverev during the tournament.

He was unhappy with his game playing Zverev again during the final.

"Obviously, he had big serves. I wasn't returning well. I wasn't making him, so to say, making him move too much. I was making way too many unforced errors. From 4-4 in the first set, my game really fell apart, to be honest," he said, while crediting Zverev's solid play.

The top-ranked Djokovic has been the champion or reached the final in seven of his previous eight tournaments.