(Repeats story first published on Dec. 18) By Martyn Herman LONDON, Dec 29 (Reuters) – There comes a moment in all great sporting careers when the puzzle fits together and for Kei Nishikori it arrived on a sweltering early September afternoon in New York. It was there that the young kohai (Japanese for protege) humbled the master, in this case Novak Djokovic. Nishikori beat Roger Federer in Miami and had Rafa Nadal on the ropes in Madrid early in the season, but this was against the ruthless world number one in the U.S. Open semi-final, having just played back-to-back five-setters. …