Footage of what is reportedly Novak Djokovic's first-ever practice session as a child has re-emerged following his victory at the US Open.

Djokovic achieved an incredible feat at the recent US Open. After having won the Australian Open and French Open titles earlier this year, the 36-year-old flew through to the final of the New York major, only dropping sets against one of his opponents along the way.

In the final, he faced World No. 3 Daniil Medvedev and defeated the 27-year-old in straight sets, 6-3, 7-6 (5), 6-3. In doing so, Djokovic became the only player to have ever equaled Margaret Court's record of 24 Grand Slam titles.

Following this incredible achievement, home video footage of a four-year-old Djokovic attending his first-ever tennis lessons has re-emerged on social media. The video begins with the caption "Training, June 23, 1991, First Training Session."

In the video, he is taught about how to swing the racket and where to place his feet. Then, in the second training session, Djokovic can be seen picking up tennis balls on the court as someone behind the camera, possibly his parents or a trainer, discuss the young child's love for the sport.

"Let him fall in love with it," says one, before another says, "Not only love it, but you know, he kind of... Gets a sort of obligation and a habit of daily content. And according to me... He's already... It gets under his skin..."

At one point during the clip, his trainer cried "Look, a champion, he knows!", referring to the youngster, probably without realizing just how true those words would become years later.

The video also shows what is reportedly the third day of training, with his trainer joking about having ice cream and pancakes after practice. In a cute moment, Djokovic can then be seen enjoying an ice cream with his family at the end of the video.