The great crowd was subdued, even taut, when Sprinter Sacre was first paraded before them and his trainer, Nicky Henderson, later confessed his worry that he might have to retire to the medical room in fear of a heart attack.
It is the anxiety which comes with the promise of the greatest performance, the possibility that we might just be carried into another dimension, and certainly it is true that some extremely strong men were frequently rendered breathless when Muhammad Ali pranced into the ring in the days of his prime.
Often we don't need too much encouragement to make our own dreams and then so many of them are destroyed. This, though, was never the possibility today.
Sprinter Sacre promised the stars and then he delivered them, each one a little brighter than the last.
Today the dreams were not only saved, they were given quite extraordinary flight.
Henderson, at 62, was both delivered from his crisis of nerve and sufficiently exultant to declare: "This is getting into the realms of something pretty unique." No one began to demur.
Indeed, when all the data came in, all the stunning detail of his 19-length victory over the fine ex-champion Sizing Europe, the scale of this seven-year-old gelding was no longer a matter for speculation.
There are so many intangibles in the timing of great races – the weather, the surface, the particular hazards and obstructions – but when the Timeform rating of this performance was set against past achievement Sprinter Sacre was provisionally announced as the owner of the most remarkable figures since their ranking system was installed nearly 40 years ago.
When bringing a hush to the valley, then drawing a huge ovation of not so much sated emotion but bone-deep admiration of a performance delivered so thrillingly, Sprinter Sacre was seen to have outstripped such modern titans as Desert Orchid and Kauto Star and was, with so much of his career yet to unfold, just a shade behind the nonpareil of jump racing, the great Arkle.
It meant that Henderson's assessment was made to seem quite modest. Sprinter Sacre not only justified the clamour he created here last year when he gained his dazzling first win at the place where equine legends have so often announced themselves in the most unforgettable terms, he brought to it a new depth, a new sense that here was something so strong, so utterly exceptional we would have it always.
Because he has so much speed, because it burns away all opposition as though it is not so much a challenge as an act of extreme presumption, only a freak of nature might allow Sprinter Sacre to cover the longer three-mile-plus distances of such as Arkle and Kauto Star. But who would quibble about the extent of the gifts which came to this extraordinary animal who arrived at the unsuspecting Henderson's yard as an owner's allocation of a job lot of French bloodstock?
"I didn't know what I had, how could I?" Henderson mused. He was a man who had struck, almost innocently, an unfathomably rich vein of gold. But if that was the purest fortune, there was the terror of guarding such precious talent. "Yes, it has been terrifying," Henderson admitted. "So many things can go wrong, that is the horror." Today, though, there was the untrammelled joy of not only surviving the ordeal of trust and care but the fulfilment of an extraordinary mission.
Sprinter Sacre won the Queen Mother Champion Chase over two miles and if he ever goes a longer distance it will be a matter of fierce calculation. However, there was never a question that the yearning to see a great horse fill the vacuum left by the beguiling Kauto Star would not be handsomely met.
Henderson said: "I hope people enjoyed this today for what it was – something quite extraordinary, something I don't think we should ever forget."
The jockey Barry Geraghty was no less consumed by the scale of and the drama of the achievement.
There was an awe in his voice when he declared, "I've never ridden a horse that does it all so easily. He has such power and scope, and that gives him all the time he needs. He's like a top footballer, like Pele on the ball, who used it so easily because his speed and his power and skill gave him the time to do it.
"He made a mistake at the ditch, the first he's ever made, but he knew what he was doing and it really wasn't a mistake. He was long into the fence, really long, and he put down on me, but off that ground he was telling me it was the thing to do. Then he winged the next, then the last."
It was at that moment that Henderson knew, finally, that he would not be in need of anyone's medical attention, only the glass of good champagne he now grasped as he said: "This horse is just very, very special. Of course you enjoy it, every minute of it, but you still have to do it, the fences still have to be jumped, you still have to get through the days and the weeks and the months and when you talk about next year it can seem a very long time."
It was enough, at least for a little time, to live in the moment, to enjoy it and to be engulfed by it.
There have been many such days here in this valley. There has been Arkle, the majestic, unparalleled Arkle soaring to such astonishing equine achievement. There was Desert Orchid, besieging the regard of the nation, and there was Kauto, who when he was gently ridden out of last year's Gold Cup by Ruby Walsh left a new craving for another horse to fuel the dreams.
Now the demand has been met, more profoundly than most sober judges could ever have imagined.
Few great performers, human or equine, have ever been examined quite as closely as Sprinter Sacre was today. For the moment, at least, it seems hardly enough to say that he passed his test. What he did, of course, was fly beyond it.
Coral have donated a £100 bet for each day of the Festival, any proceeds going to charity.
Day three Paul Struthers, chief executive of the Professional Jockeys' Association
American Trilogy (2.05)
I'll go £50 each-way. He's a past Festival winner who is back down to a good mark on firmer ground.