There is no more terrible beauty in sport than when one of its great stars reaches into the past to find again that singular quality that first dazzled the world.
It is especially so when he does it in the knowledge that it might just be for the last time.
Thierry Henry filled the Emirates Stadium with as much a sense of this as the old thrill of his perfect technique and surreal calmness under pressure.
As Henry produced the most daunting requirement of an ultimate comeback artist, a flawless cameo of the work that graced his time at the peak of football, you could certainly understand easily enough his old mentor Arsène Wenger's enraptured belief that all his other problems, and not least his need to push back the clock with the brief hiring of the old hero, could for one night at least be pushed aside.
Wenger said it was like a dream, and so it was, but it could so easily have been a nightmare. Comebacks often are, which is why Eric Cantona's most vivid post-retirement fantasy is to be the president of France, why Paul Scholes was stunned when Manchester United last weekend pressed him back into action and Barry John, maybe the most gifted rugby player ever produced by Wales, rejected all overtures to return to the scene of his old triumphs after walking away at the age of 27. He was known as the King and he said that the expectations almost drew the breath out of him.
Henry is more like George Best, who, however vertiginous his decline, never lost his desire to show his skill and was delighted when a goal he scored in the last days of the old North American Soccer League was the subject of endless TV re-runs.
How many times will we see Henry's goal against Leeds United, whose dogged resistance to Arsenal's domination was melted down in just 10 minutes by the aura and killing certainty of the Frenchman's talent?
It will be impossible, surely, to become weary of those re-runs any time soon because not only do they present a beautiful goal, they also show us the meaning it had for the man who scored it.
For a little while, Henry's exhilaration was almost disturbing. He embraced Wenger before a passing acknowledgement to Alex Song, who had seen him lurking in his time-honoured striking position on the left and delivered the perfectly weighted pass. But for a little while he might have been the single occupant of the entire world.
It was an extraordinary, uplifting spectacle but it did speak of the need for that recognition that plainly grows down the years and becomes, in the last of them, something close to an ache.
Outside of Henry's sport you probably have to go back to 1987 and ringside at Caesar's Palace in Las Vegas to recall quite such a spectacular reincarnation of a special talent. That was when the great Sugar Ray Leonard came back after two retirements provoked by the need for eye surgery after a detached retina brought "floaters" to his vision while training for a fight five years earlier.
Leonard defied medical opinion and the advice of his people when stepping in against the formidable Marvin Hagler. He won a split decision and some swore that his opponent had been robbed. What no one could deny was that Leonard had produced plenty of evidence of his old brilliance, stealing rounds with bursts of stunning speed and timing, and when his arm was raised it was easy to remember a conversation of a few years earlier.
He had been encountered at the weigh-in of a fight between Hagler and Roberto Duran and he glumly conceded that life had lost a vital edge. "Yes," he confessed, "I wish so much that I could be up on that stage in front of all those cameras and then in the ring tomorrow. Those guys are standing at the centre of the world. You can see where I am. I'm in the crowd."
Henry had his first intimation of such exclusion when he arrived in Barcelona. He found himself in the chorus line accompanying such marquee names as Lionel Messi, Xavi and Andres Iniesta. Now he plays for the New York Red Bulls. This week, like Wenger, he journeyed back to the best of times.
The trick, as Leonard discovered soon enough, is to avoid the worst of endings. Before a terrible beating by Terry Norris at Madison Square Garden, Leonard said after one of his last work-outs, "You ask me why I'm going into the ring again... it's simple. I'm going to do the thing I will always do best. I'm going to fight."
It wasn't his last fight. Hector Camacho beat him inside the distance. Everyone told Leonard he should have quit that day in Las Vegas. Of course they were right. But then watching Thierry Henry this week was a reminder of maybe why he didn't.