Novak Djokovic is one of the world's top tennis players, but don't expect him to excel in all versions of the game just yet.

Djokovic tried out some wheelchair tennis for a charity event in Melbourne, Australia on Wednesday, playing against Australian wheelchair tennis pro and two-time gold medalist, Dylan Alcott.

While the Serbian champ has no such trouble hitting balls against Alcott while standing, the tables really turned when Djokovic tried playing from a wheelchair.

"Oh my god, I have to play tennis. How do you do it?" Djokovic asked, while trying to figure out how to turn his new chair.

No wonder Djokovic kept asking Alcott if he could play it down the middle. If there was any doubt in your mind before, the video makes it pretty obvious -- wheelchair tennis is hard as hell.

The action starts from 1:30 in the below clip.

The charity event was called "A Night with Novak Djokovic," where Djokovic was helping to raise money for his foundation which supports preschool education for children.

Djokovic tried his hand at other sports too, like Australian rules football, netball, cricket and football (a.k.a. soccer) -- where he so happens to be a left-footer. What a good sport.