It is true that nowhere on earth can accelerate the ageing process quite so dramatically as the boxing ring. Even so, the decline of the master Cuban Mario Kindelan in Bolton against the hugely hyped Amir Khan was remarkably profound by any standards.
The degree of it indeed made some of the claims being made on behalf of the teenager, who was such a warm and exciting presence in last summer's Olympics in Athens, distinctly disquieting. At Bolton the story had progressed to an alarming degree. We were told Khan is a certainly to be Britain's youngest professional world champion since Naseem Hamed. The occasion was grotesquely inflated, and Kindelan's display gave such projections no serious foundation.
Perhaps most worryingly of all, Khan, a model of boyish charm and modesty in Athens, got so far ahead of himself on Saturday he was announcing his intention to retire by the age of 25. But first, of course, he must have a career in the pros. Though his distaste is on record for the arrogance that Hamed displayed before meeting for the first time a fighter of the highest class and condition, and being thoroughly thrashed, even mocked by Marco Antonio Barrera, Khan had acquired some of his predecessor's trappings when he came into the ring to face a bemused Kindelan.
There was the showy entrance and the rapturous reception. There was the gushing television coverage; above all there was the assumption that Khan's ascension to a world pro crown was simply a matter of brief time.
Some time before Barrera got the chance to bring Naseem Hamed back to earth, the Mexican worked brilliantly in a tough Los Angeles gym and then said, "Naseem thinks he is a star - but what of, a circus?" A circus is what we had in Bolton on Saturday night.
Meanwhile, in Latin America and the Far East, young fighters of great toughness and talent were polishing their gifts in the hardest trade. Let us hope that in a few years' time one of them will not have reason to appraise Amir Khan with the same contempt that Barrera once had for Hamed.