The heavy artillery has rolled into position. Bernardini has arrived from New York, George Washington from Tipperary. Aidan O'Brien emerged from the quarantine barn - something his colt will not do until this morning - wearing a jacket emblazoned "Gorgeous George". The local reporters crane forward to catch his gentle voice, and are surprised by the immodesty of the words. Is he worried about Bernardini, hot favourite for the Breeders' Cup Classic tomorrow? "We've never regarded other horses as dangers to George," he said mildly.
Bernardini, whose own looks are pure Hollywood, stretched his limbs on the track and afterwards preened for dozens of photographers as he was sponged down under blushing trees. The preceding morning had been vile, but Bernardini was consecrated by a limpid autumn day. Vapour rose from his mahogany flanks into the cold blue air, but the sense of divinity, of mystery, dissolved in the modesty of the ritual, soapsuds trickling between his hindlegs and his tail hanging long and wet.
Unquestionably, Bernardini faces his toughest assignment tomorrow. Quite apart from the rogue male from Ireland, he must deal with the blue-collar slogger, Lava Man, and a champion imported from Uruguay, Invasor. And while he has certainly earned the right to top the bill, having lit up the second half of the American season, in a sense he can never overcome the poignant circumstances of his breakthrough.
For Bernardini did not flourish in time to run here in May, when the Kentucky Derby instead seemed to identify another colt, Barbaro, as the glory of their generation. He won by six and a half lengths, a margin unmatched in 60 years. He was unbeaten, he was unequivocal, he even seemed blessed by destiny - trained as he was by a legitimate American hero in Michael Matz, an Olympic medallist who had once saved children from a blazing plane.
But when Barbaro went on to the second leg of the Triple Crown, the Preakness Stakes, his career ended in abrupt catastrophe. He had just left the gate when one of his hindlegs crumbled, right in front of the grandstand. As the field returned, Bernardini stretching clear, the crowds remained transfixed by their stricken hero, hobbling grotesquely on the margin.
And, during an attritional recovery, they have stayed with him every step of the way. They have marvelled at the horse's own spirit and the skills of those tending him, not least when laminitis compounded their problems. Barbaro is still not out of the woods, but the guarded expectation is that he will make it, that he may even have a career as a stallion some day.
Now Matz is back at Churchill Downs, with a new perspective on the vanity of what had seemed indelible joy. He saddles Round Pond in the Distaff tomorrow, but there is no mistaking the ghost at the banquet. Every time Bernardini runs, Matz wonders what might have been. "It's sad it never happened," he said. "Sad for everybody. It might have been one of those great rivalries between the two. They're both good horses, they both win races. Who would have been the best? That's for all to guess. But I'm a little biased, don't you think?"
A man of innate composure and dignity, Matz does not dwell on the hopes he had to bring Barbaro back here, for the Classic, and to Europe next year. "It's such a shame, but maybe it's a bigger thing he has done," he said. "Bringing the racing public together - and the public in general. The response has been unbelievable. I got over 40,000 emails, and that's just me, never mind the owners. People have brought him flags sent by wounded soldiers in Afghanistan. The support has been overwhelming. He has brought a lot of people together."
Barbaro's leg is still in a fibreglass cast. Outside his stall in Pennsylvania are letters from schoolchildren, a statue of St Francis. Sheikh Mohammed, who owns Bernardini, sent him holy water from the River Jordan. Matz considers himself a humble conduit of a collective experience.
"I visit him every day when I'm at home," he said. "He's done so much for me, it's the least I can do for him. I change his bandages, or walk him. He gets out twice a day when the weather's good. He's eating well, putting on a bit of weight. He's over 1,100lb now.
"But things can still go wrong, in so many different ways. We just have to keep our fingers crossed that he keeps going the right way.
"If I never get another horse like this, at least I had him once. I thought for sure this horse would win the Triple Crown. Then when he foundered, I thought: 'They're going to put him down.' But he didn't want any part of it."