Novak Djokovic did not think there was any "breathtaking tennis" in his 6-4 6-1 triumph over Alexander Zverev at the ATP Finals.

The Serbian staved off two break points at 4-4 in a closely contested opening set, but a costly double fault on set point from Zverev gave the world number one the initiative.

Third seed Zverev only won one more game as he committed numerous unforced errors and Djokovic closed out the match inside 67 minutes, moving to the brink of an eighth appearance in the semi-finals.

"I don't think it was breathtaking tennis to be honest from both of us but a win is win," said the 14-time grand slam champion in an on-court interview.

"I thought I played well from midway through the second set, I started to swing through the ball but I haven't served that great."

"He obviously made a lot of unforced errors that allowed me to win, probably easier than expected. Especially in the second set he wasn't close to his best."

Djokovic displayed his typically brilliant defence to keep points alive, with his flexibility leading to his interviewer Annabel Croft calling him Mr Bendy.

With a chuckle, he replied: "Mr Bendy? That's a first!"

"I've been called different names for the flexibility. I'm obviously relying on it a lot ever since I was a boy, starting to play tennis and I was skiing a lot in those days and playing different sports."

"I was fortunate to be around people who emphasised the importance of stretching for the longevity of the career. It's paying off right now!"