India, Sept. 6 -- In the early stages of his career, Novak Djokovic was the villain. He was the young gun who dared to dream even as Roger Federer and Rafael Nadal reigned supreme. He played through jeers more often than not, convincing himself that the boos were actually chants of "Nole," his nickname.

But he's played and achieved long enough to see himself now become a hero. And on Friday night, at a packed Arthur Ashe Stadium, the 38-year-old from Serbia did not have to imagine anything. There were loud, deafening cries of "Nole".

Djokovic is the most decorated Grand Slams singles player in the Open Era, with an all-time joint record of 24 titles. He has won every important title the sport has to offer. But now he is an underdog with...