It was just before 5pm local time, in the autumn of 2011 in New York, that Novak Djokovic hit what is widely regarded as one of the best, and most beautiful, strokes in the history of tennis. His opponent, Roger Federer, was on a roll. The Swiss had won two straight games and now stood on the cusp of the US Open final. He led 40-15. He had two match points. And he was on serve.
The crowd was in a state of near euphoria. Federer is popular in the Big Apple, and a wall of noise had been building throughout the deciding set. Djokovic was almost forgotten in the mêlée. Only his small entourage seemed to be on his side. His face was ashen.