At 36, Novak Djokovic is clearly still at the peak of his powers.

Sitting atop the world rankings, he is coming off a season in which he won three majors and is favoured to claim a staggering 11th Australian Open crown this fortnight at Melbourne Park.

The longer he continues his career, the more questions Djokovic will face about when he will consider retiring.

It is a topic that has been broached publicly with the 24-time major winner during the past year. And it was raised again after his 6-0, 6-0, 6-3 thrashing of Adrian Mannarino in the Australian Open fourth round on Sunday.

Djokovic suggested he would know when it was time to hang up the racquet.

"I feel while being number one and still on top of the game, I don't feel like leaving tennis in that position," he said.

"I feel like I want to keep on going. When I feel that I am not able to compete at the highest level with the guys and be a contender for a grand slam title, then I'll probably consider going into retirement.

"But that can change, obviously. A lot of things can change. I'm not a teenager anymore. I'm a father and a husband.

"A lot of things happening in the private life off court that I enjoy, that require my attention, my presence, my energy.

"Still, I'm really blessed to be where I am. Let's see how far it goes."

At least for the time being, a lack of motivation is not an issue for Djokovic, who turns 37 in May.

"I always look for the best performance from myself," he said.

"It's (motivation) still there. The fire is still burning. I think that's what allowed me to be where I am and achieve the things that I have achieved.

"Part of me, of course, is enjoying the process. Otherwise I wouldn't be playing.