In a dramatic photo-finish of inches, with the likely result changing frame by flickering frame, stride by stretching stride to the line, the 6-1 shot Sir Percy stuck his head out as the camera clicked and won the 227th Derby by the minimum margin, a short-head. There was not much further between the next three home, Dragon Dancer, Dylan Thomas and Hala Bek. It was the tightest Derby finish since 1913.
But in the wake of yesterday's thrilling denouement came the chilling other side of the sport's spinning coin. Inside the final two furlongs Horatio Nelson, the mount of Kieren Fallon, broke a foreleg, his gallop reduced in an instant to a grotesque stagger. Fallon pulled up and dismounted and the colt was taken from the course in an equine ambulance, but his injuries proved too severe for him to be saved.
But to the victor, the spoils, in this case £740,695. And the reward was a thorough justification of principals. Sir Percy, who is trained by Marcus Tregoning for retired solicitor Anthony Packenham and his wife Victoria, cost just 16,000 guineas as a yearling, back-pocket change in the bloodstock world. Despite his bargain-basement price tag, he proved himself one of last season's top juveniles and after he won the Dewhurst Stakes, telephone-number bids started coming in.
The Newmarket-based Packenhams kept their nerve and kept their young star. And all the faith, judgement and patience have been gloriously rewarded on the greatest stage of all.
But oh, it was close. As Dylan Thomas, the perceived third string from Ballydoyle - both Horatio Nelson and Septimus were ahead of him in the betting - took the initiative from his 17 rivals after a couple of furlongs Sir Percy, with Martin Dwyer riding in only his second Derby, was nearer last than first.
Dylan Thomas still held the call sweeping down the hill to Tattenham Corner and into the straight, closely pressed by Dragon Dancer. The pair began to stretch their lead, with no immediate pursuers and going to the final furlong they were still head-to-head in front.
But then, towards the middle of the track, the 2-1 favourite Visindar began to make his move, with Hala Bek alongside and Horatio Nelson on their heels. The three came tight together and at this point Horatio Nelson sustained his fatal injury.
Inside the final half-dozen strides Visindar gave best, Hala Bek was left without cover and betrayed his inexperience - he had raced only once before - by veering away from Philip Robinson's whip. Once balanced, he ran on again with a will.
And while Dylan Thomas and Dragon Dancer duelled, and Hala Bek rallied there, charging from the pack into a charmed gap along the rails, was Sir Percy, gallantly answering every one of Dwyer's questions in his late charge to glory.
"An exceptional horse," said the jockey, "with a tremendous turn of foot. It was a rough race, though I really enjoyed it. I just had to go where there was room, and take chances by going up the inside and hope the gaps would come. I wasn't sure if I had got up; I just kept my head down and hoped. And he dug deep."
Dwyer had had a fall at Bath the previous evening, but Sir Percy's road to Epsom had been even bumpier. The son of Mark of Esteem was stiff and sore after his fine second place in last month's 2,000 Guineas and Tregoning and his team at Kingwood stables in Berkshire had a race against time to get him ready for his date with destiny.
"This win is down to Marcus first and foremost," added Dwyer, "all I did was sit on the horse." It was a first Classic victory for Tregoning, 46, who served his time with the late Dick Hern in the days of the 1989 Derby winner Nashwan and is nine years into his own career.
"After the 2,000 Guineas it was my worst nightmare when Sir Percy was not quite sound behind. We even wondered if we should go to France for the French Derby [at Chantilly today] where the track is flatter," he said.
"Our physiotherapist has done an amazing job in building up his muscles again. But every credit to the horse. We were struggling to get him here, but he's a street fighter and a battler." Tregoning was let off with a warning after being stopped for speeding en route to the track, but his dash was nothing compared with Sir Percy's.
The Derby is the race that sets the middle-distance standard for the three-year-old generation and although Sir Percy now wears the mantle, after yesterday's blanket finish others will be tugging at it.
For instance Dragon Dancer, the 66-1 outsider who has yet to win a race but failed by only a whisker in the biggest of all under Darryll Holland. "I felt sure he could get a place," said the trainer Geoff Wragg, who used to train Sir Percy's dam Percy's Lass, "but this really was so near, yet so far."
Horatio Nelson's bid seemed ill-starred. At the start, Fallon trotted him up and down several times, seemingly uneasy about the colt's action, though he was judged fit to run by trainer Aidan O'Brien.
It was a grim reprise of events in the States last month, when the Kentucky Derby winner Barbaro, about whom there were doubts after he broke from the stalls before the Preakness Stakes, suffered a career-ending leg injury during the race, though his life was saved.
Quote, unquote: 'The man to thank is Marcus. He got us here'
It all opened up for me. The man to thank is Marcus [Tregoning]. He did a good job just to get us here, and in such great form. It was a rough race and I had to go where I could get a run. He [Sir Percy] pulled up sore in the Guineas and missed a fair bit of work - I didn't see him until last week, but he showed a tremendous turn of form. I'm so pleased.
Martin Dywer, winning jockey
I'm still pinching myself. To have a finish like that was unbelievable. The one thing we knew was that he had a turn of foot. I saw him coming up the rail and thought, wow, he just might do it.
Victoria Pakenham, co-owner
It was a fantastic race - I did think that Hala Bek was going to get up but that was brilliant. I was stopped for speeding on the way here and was late for the parade, but I said I had a runner in the Derby and luckily he let me go.
Marcus Tregoning, trainer
So near, yet so far. He was going well all the way round until the last stride.
Geoff Wragg, trainer of second-placed Dragon Dancer
1 Sir Percy 6-1
2 Dragon Dancer 66-1
3 Dylan Thomas 25-1
Ridden: M Dwyer
Trained: M Tregoning
Owned: A Pakenham
Distances: Short head, head
Favourite: Visindar 2-1