Pyledriver battled back in the closing stages to deny Al Aasy and lift the Coral Coronation Cup at Epsom for his first Group One triumph.
Al Aasy headed Martin Dwyer's mount in the final furlong, but Pyledriver (8-1) rallied in determined fashion on the rail to snatch the verdict by a neck for the relatively new training partnership of William Muir and Chris Grassick.
Dwyer made a brave move at halfway when he took the bull by the horns and sent Pyledriver into the lead after Highland Chief had taken them along.
Albaflora tried to put in a challenge, but it was Al Aasy who cruised alongside under Jim Crowley and looked like he could take the leader.
The 7-4 favourite did hit the front but, with the rail to help, Pyledriver regained the initiative in the dying strides, as the first two drew seven lengths clear of Japan in third.
It was a landmark success for Dwyer who has now won all three of Epsom's showpiece events, after the Oaks on Casual Look in 2003 and the Derby on Sir Percy in 2006.
Dwyer said: "It's great for everyone - it's great for the whole team, great for connections.
"He's redeemed himself from last year (when unplaced in the Derby). It wasn't his fault - the race went wrong. But what a way to do it - I'm proud of the horse.
"On a personal level, I've got to say there's times when I've hated racing, hated it, had bad days and driven home in a bad mood.
"But days like this, I can't describe in words what I'm feeling inside - it's just euphoria.
"This is a wonderful sport - anyone can achieve things, great things. I'm nearly crying - what's wrong with me?
"It's been a long time between drinks for me personally, and it's hard to get horses as good as this and hard to stay on them.
"They don't win every Group One, and you always get people criticising from the outside - and I've got to thank the owners and William for sticking by me. I think we've justified it today.
"It's a shame (my family) can't be here, but I'm sure they'll be watching on the telly - and they might be happy to see me tonight!"