Novak Djokovic's four-year-old just watched his dad play at a tournament for the first time.

While most spectators would assume Novak Djokovic’s latest win was particularly significant because it’s taken him one step closer to holding all four grand slams at once, for the 32-year-old, it was special for a different reason.

For the first time, his four-year-old son Stefan watched his dad play.

Speaking on court after the match, Djokovic said, “It’s a very special day for me as it’s the first time in my life that I have played in front of my son.”

“He showed incredible patience to sit there for an hour and a half. Usually, he’s not that patient with tennis.”

While Stefan is likely no stranger to his dad’s tennis ability, Thursday’s match was the first time he’s watched from start to finish.

It’s not, however, the first time tennis fans will have seen Stefan celebrating one of his dad’s wins.

When Djokovic won Wimbledon last July, his then three-year-old son was watching in the crowd as he accepted his trophy. He hadn’t been allowed on Centre Court to watch the actual match, because children under five aren’t permitted on show courts at Wimbledon. The rules are more relaxed for the presentation.

When you spot dad with the trophy ????#Wimbledon @DjokerNole pic.twitter.com/POO2uXZWRq

— Wimbledon (@Wimbledon) July 15, 2018

“It feels amazing. For the first time in my life I have someone screaming ‘Daddy, Daddy!'” Djokovic said at the time.

He also acknowledged last year that his son had been a particularly motivating factor in his recovery from injury.

“Actually, I didn’t talk about it but it was one of, if not the biggest, motivation I’ve had for this Wimbledon this year,” he said after winning the tournament.

“I was visualising, imagining this moment of him coming to the stands, cherishing this moment with my wife and me and everyone. It’s hard to describe.

“I never had him in the box watching the tennis match. I was hoping that Wimbledon can be that tournament because he’s big enough now I think to stay quiet maybe for 30 minutes or so.

“There are special rules here so we have to respect them,” he said.

Djokovic explained that it was seeing the children of his rival, Roger Federer, in the stands that made him aware of how special it would be to have his family present.

“Roger (Federer) had his girls and his boys as well, I think, last year and the years that he won at the trophy ceremony, so I was hoping I can have Stefan, too.

“He was not there til the very moment when I was walking to get an interview. He walked in. So that was just a moment that I will carry inside of my heart forever.”

Novak Djokovic is currently number one in the Men’s Singles Ratings.

At the French Open, he’s about to face Italian Salvatore Caruso, who is ranked number 147, to secure a place in the top 16.