Great buildings may be refurbished. Great works of art can be restored. But great sportsmen have no way of defying the ravages of age. Both Pete Sampras, with his record 13 grand slam titles, and Andre Agassi, with major titles on all surfaces, are entering the twilight of their careers, and neither is as twinkling fast on his feet as he used to be.
Yet between them they served up - an the emphasis was very much on serve - an evening of remarkable white hot intensity and spellbinding intoxication under the floodlights at Flushing Meadows, with Sampras winning 6-7,7-6,7-6,7-6 over three hours 32 minutes to reach the semi-finals of the US Open.
The Pete goes on, and the Pete goes on, was the thumpingly, unstoppable rhythm underscoring this 32nd meeting between the two American giants of the modern game, with Sampras now having won 18 of them, dating back to 1989.
Agassi (31), had done little wrong. Neither men dropped their serve throughout, but Sampras, one year younger, served so fearsomely well that Agassi, the master returner, was unable to either blast, craft, or somehow fiddle a break.
Sampras had entered his 13th US Open, four of which he has won, in a deep and darkening trough, and without any sort of title since he so memorably defeated Australia's Pat Rafter 14 months ago to record his seventh Wimbledon and record 13th grand slam win.
Whereas Agassi has resurrected, restored and thoroughly enhanced his career over the last two years, Sampras had begun to feel time was standing still. Last year, at this same tournament, he was crushed in the final by a 20-year-old Russian Marat Safin. To many it appeared the king's sword had shattered, that Merlin's magic wand was broken.
In the Australian Open this year he lost to fellow American Todd Martin in the fourth round, while at Wimbledon his centre court supremacy was cut from under his feet by the young Swiss, Roger Federer. Sampras's table talk last week of continuing for another "five, six, or seven years" was met with pregnant silence and averted eyes.
But he was riled. The defeat by Federer at Wimbledon was an intense hurt. He has always hated defeat; neither was he prepared to accept it. The fires, seemingly all but out, began to smoulder and against Rafter in the fourth round the Phoenix began to arise.
There were those who believed Wednesday's night's match to have been one of the greatest ever. Perhaps. Certainly the tennis was of a supremely high standard, with the Sampras serve was back in its pomp. But for all the undoubted intensity and quality there was a pervading feeling of time past, of men whose days had all but gone.
It may sound perverse, but for this match to be counted as truly great it remains necessary that Sampras goes on to win the title. So far he has beaten his greatest rival; he has not beaten the new kids on the block. Should he do that over the weekend, then this quarter-final may, retrospectively, acquire the true bloom of a classic.
Jennifer Capriati hardly bothered to consider the implications of a revenge over Amelie Mauresmo, or that her 6-3, 6-4 victory carried her to the women's semi-finals for the first time in a decade. "I'm just thinking about how everything's changed," she said.
As far as the world is concerned Capriati has changed dramatically. She has been painted with a different persona, reformed, even resurrected. Certainly she is a very different tennis player, slimmer, stronger, even more dangerous than ever with the angles of her counter-hitting forehand, even quicker than she was, and, crucially, more resilient and durable. All this gives her a vision far beyond mere atonement for her Berlin loss to Mauresmo or of repeating something she achieved here (New York) when she was still little more than a kid. Add a very different tennis scene, with the women's Grand Slam TV viewing figures now sometimes surpassing the men's, and Capriati has the capacity to transcend tennis. To become an icon for misused adolescents, perhaps, to become a beacon for victims of distorted parental priorities. At 25 those priorities are clearer and much, much, more appropriate. Capriati is aiming for a remarkable sequence, beating the U.S. Open and Wimbledon champion Venus Williams today, winning her third Grand Slam of the year tomorrow and becoming world number one on Monday, but not to fell ashamed if she doesn't achieve them.
"If I play my game, my way, and play it well, I have as good a chance as the other three (semi-finalists)," she said. "Then we will see what happens." The right mentality. And with two advantages. The win over Mauresmo, in which Capriati's application wobbled only once, helped her feel how much better she sits on opponents when they are down, how much that vulnerable mind has healed. And her last meeting with Venus, in Miami in March, produced a multiple frustration which could act as a helpful spur today. Capriati had eight match points, and all eight got away.
Details in SPORTS ROUND-UP ... n Guardian Service.