Tennis world number one Novak Djokovic told his family that he was quitting tennis after suffering a bad loss, his wife has revealed.

The Serbian is considered one of the all-time tennis greats but spoke of quitting the sport to his wife Jelena last year after suffering a fourth round Miami Open defeat to Roberto Bautista Agut in March last year.

Speaking in the latest episode of In Depth with Graham Besinger, the pair opened up on the impacts being a top-level athlete can have on their marital life.

Jelena lifted the lid on the troublesome time last year in which the defeat in Miami coincided with another disappointing defeat for the 17-time Grand Slam Champion against Philipp Kohlschreiber in the third round at Indian Wells.

"He said to me that he's quitting and that's the truth", said Jelena.

"He lost in Miami. It was a terrible loss. And then he just, you know, gathered all of us and said, 'You know guys, I'm done.' And I was like, 'What?' And he goes like, 'Yeah.""

He said, 'Edoardo, you can speak with my sponsors. I want to be clear with them. I don't know if I'm stopping for six months, a year or forever.'”

In the interview conducted just before the COVID-19 pandemic forced the shutdown of all tennis, Novak also revealed on the challenge his continued success in the sport has had on his marital life, and the sacrifices Jelena has inevitably had to make in order to support him.

Over a two-year period, Novak Djokovic won 158 matches, including six majors, one of the most dominant winning streaks in tennis history. But it came to an end and Novak was left with the realization that his happiness had been dependent on his success on the court.

"I really feel my relationship became deeper, more significant, more intrinsic. And I realized, actually, up to that moment, that (my) relationship with some of the closest people in my life were quite superficial and shallow, because I just didn't know how to handle that", Djokovic told Bensinger.

"And that, uh, she, it's inevitable that she has to endure the same journey as I do at the same time, otherwise we can't stay together. And, uh, and, and I'm really grateful and happy that, uh, she embarked on the same journey, her own journey, but parallell at the same time as, as I did."