Novak Djokovic defeated Joao Sousa in straight sets to reach the US Open quarter-finals for the first time since 2016. Since winning Wimbledon, things seemed to have changed almost overnight for the 13-time Grand Slam winner in the eyes of many people.

Speaking about whether these changes had affected him, Djokovic stated, 'First I have to say that tennis is not determining whether I'm happy or not. I'm a father of two kids. There is a lot more happening in my life than tennis only.' He also added, 'So, of course, I do feel better, if I get to win a tennis match that I worked very hard for.

If I lose it, you know, it's not going to change the course of my every day for a certain amount of months or a certain period. It wasn't like it used to be. When I got that blessing to become a father, things have changed.

You added more meaning and more purpose to your life, more responsibilities. So there are things that make you happy even when you lose a tennis match. So that's the first thing. In terms of tennis-related only, of course I felt huge relief when I won Wimbledon this year because of the period of last couple years before that, what I've been through with injury, inspiring myself to get back on the track and try to win majors and be one of the best players in the world.

Being absent from the tour for six months allowed me to have time for reflection for, you know, taking a larger perspective at things and understanding how I want to come back to the tour, how I want to play. Things I wanted to always work on but never had time, I had time.

Well, I haven't really played because of the elbow, but still, I had time to reorganize my whole life. So I'm grateful for that opportunity.' ALSO READ: Boris Becker: 'Rafael Nadal will win US Open. I won't be Djokovic's coach'