The best pure tennis match any of us are ever likely to see was played on Wimbledon Centre Court three years ago. Rafael Nadal beat Roger Federer in a final of such exquisite balance and marvellous sportsmanship you wished it would never end.
Federer played a backhand down the line, under immense pressure, you had to lock away in the memory as you would a combination by Muhammad Ali or the turn of a great thoroughbred's hoof.
However, sport will rarely provide a better reason to stay up deep into the small hours than the sight of Novak Djokovic drawing to a close a year of such coruscating brilliance and unrelenting effort Nadal, no less, reckoned it would almost certainly prove unsurpassable.
"The guy is doing unbelievable things," said Nadal, and from the appreciative look on the face of his conqueror it was fair to assume that you could have ransacked every corner of the world of sport without finding a witness whose testimony would have mattered more.
While the remarkable details of Djokovic's year will always stand imposingly in the record books – three Grand Slam titles, two defeats in 66 matches, one to Federer, one a retirement through injury – they may never quite convey the level of his impact, the electrifying effect of a series of announcements that he had not only joined arguably the most brilliant elite in the history of tennis but also carried the game into a different dimension.
How else can we define the extent of his progress since Nadal beat him in the final of last year's US Open?
The aura of Nadal, after all, rose apparently inexorably after his superb defeat of Federer in the great Wimbledon final. There was just one shadow over his huge stride to the status of the world's No 1 player. It was the worry of troublesome knees, compounded by the massive physical weight of his game.
Nadal was the embodiment of tennis power, the author of shots which might have been flying from the mouth of a howitzer. He was also a superb ambassador for his sport. Yet in New York on Monday night we saw more than the mere defeat of a great champion, the winner of 10 major titles, the one man who was able to stand up to the challenge of operating in the era of Federer.
We saw him relegated to a lower level of tennis mastery. We saw his confidence teased and then pummelled. We saw him stripped down to his last, immutable asset, his magnificent fighting heart.
For many, understandably, this was a matter for intense regret. Sport, after all, is not so rich in character and spirit and unswerving attachment to the highest standards of fair play and generosity that we can surrender easily the idea of Nadal in all his defiant brilliance and decency.
It is also true that in some respects Djokovic is somewhat less embraceable. A dazzling mimic, a puckish humourist, the Serb may well be but there are times when he operates on a fine line between the gut-deep excitement of his game and a certain darkness of spirit.
His violent reaction to crisis on the way to his Wimbledon title certainly shocked local sensitivities, some of which were not entirely soothed by his twinkle-eyed reaction to a question about whether he had ruined his racket the first time he swiped it against the baseline or the fourth or fifth. "I like to make sure," he said with a touch of menace worthy of Jack Nicholson.
There is something a little bit chilling about the depth of Djokovic's ambition, something as extreme in his nature as in his game. Yet what a game it is, and what a will he has to inflict it as he takes it to its limits and his opponents quite beyond their own.
Nadal took defeat with predictable grace but if it was Djokovic who required medical assistance going into the fourth set there was not much doubt about who it was in most need of rehabilitation at the finish.
Nadal dredged up everything he had in winning the third-set tie-break but his reward was not the possibility of an amazing recovery but a hollowness of performance that betrayed all he had done before.
The year-long accumulation of defeat by Djokovic had already persuaded Nadal that he was required to rethink his game, and re-assess all his strengths, in dealing with the unique and ultimate challenge of the prime of his career. Now, though, that imperative seemed to reach down to his bones.
Djokovic, in his New York fire-fighter's hat, talked respectfully of the man he had stripped down to hopelessness. He spoke of his relish for coming battles. Nothing he said, however, began to diminish the picture of a man apart – a brilliant, hair-trigger champion claiming maybe the highest ground his game has ever known.