Novak Djokovic was imitating Fiorello, whose guest was several days ago on his show, wearing a wig and limping along, before his 2nd Round match last night in Rome.
Here is some explanation for it.
"Ah, and here comes Novak Djokovic, ever the Djoker, with a wig and limping, imitating Italian showman Fiorelli who had him as a guest on his programme at the weekend. He'd promised to do an imitation and he was as good as his word. Poor old Albert Montanes tries to keep focused while the Djoker is playing to the crowd."
(thanks to humidly from youtube.com)
It's funny, funny, and funny. We can laugh anytime.
He is just GREAT! :)