LONDON (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.
Undaunted, the 24-year-old showed Djokovic scant respect, rocking the Serb with the force and relentless warrior-like spirit of his play to claim a four-set victory.
In doing so he became the first Japanese man, and the first from an Asian country, to reach a grand slam singles final.
Croat Marin Cilic cut Nishikori down to size in the final but, providing the Japanese stays clear of the injuries that haunt all top athletes, there seems little doubt he will contest more grand slam finals.
Japan has produced few male players to be taken seriously and until Nishikori, Shuzo Matsuoka had been their benchmark in the professional era, having reached 46th in the rankings.
Hence the reason a teenaged Nishikori was dubbed "Project 45" when he left the home comforts of Shimane for the endless drills and ball-chasing at Nick Bolletieri's Academy in Florida.
The project can now be classified a spectacular success even if there have been some doubts along the way.
Nishikori bettered Matsuoka's ranking in 2011 but spent the next three years hovering around the top 20 as the tennis fraternity watched on, waiting for his graduation.
Admired for his eye-catching, attacking shots, all that seemed to be missing was a touch of steel.
So last December he hired former French Open champion Michael Chang as coach and it proved a masterstroke.
He began the year 17th in the ATP rankings and with three career titles to his name.
He ended it ranked number five, more than doubled his career title haul with silverware from Memphis, Barcelona, Kuala Lumpur and Tokyo, and qualified for the elite ATP World Tour Finals.
Nishikori's 11 wins this year against players in the top 10, including beating Andy Murray at the year-ender, was bettered only by Djokovic and Federer.
"My goal after last season was to get into the top 10 and make the semi-finals of a grand slam, but I surpassed them both," Nishikori told the Japan Times.
"I got stronger as the season wore on in the second half and, I have to admit, I'm surprised by the success I had this year."
With the fiercely competitive Chang in his team, there is little chance of Nishikori taking his eye off the ball once the news season kicks off in Asia in January.
Nishikori said the American had helped him push through barriers this year when in the past he may have shirked the challenge.
"It had only been a few weeks after surgery when I went to (the U.S. Open)," Nishikori recalled.
"I was still feeling pain and I didn't want to risk it. I didn't want to go. But he told me a story from his career about getting to a grand slam semi when he had shoulder problems. So I went to New York and I ended up reaching the final.
"He constantly tells me to believe in myself."
With Chinese woman Li Na now retired, Nishikori will shoulder Asian hopes next year.
"The next goal is to win a grand slam but I know it’s not easy to go even to the semis or final, so it may take some time but hopefully I can reach a grand slam final again," he said.
Reporting by Martyn Herman; Editing by Ken Ferris