Galileo Gold stayed on strongly under Frankie Dettori to win the 2000 Guineas as odds-on favourite Air Force Blue flopped at Newmarket on Saturday.
Air Force Blue was strongly fancied to give trainer Aidan O'Brien a record eighth victory in the first British Classic of the flat racing season over a mile, but it was 14-1 shot Galileo Gold who stole the show.
Galileo Gold made his move two furlongs out and powered up the hill to beat Massaat by one-and-a-half lengths, giving Newmarket-based trainer Hugo Palmer the biggest victory of his training career.
While Palmer was elated after claiming his first British Classic victory, the legendary Dettori celebrated with his famous flying dismount following his third 2000 Guineas triumph 20 years after his first.
Palmer told Channel 4 Racing: "Frankie was so alert. It was masterful ride, he's a wonderful horse and had such a willing partner.
"When you come to a big race like this you have to be confident, otherwise there's no point in coming.
"I've never believed in a horse quite like I believe in this one and we'll keep believing for a good while yet."
Dettori added: "I had a lot of faith in this horse. My main thought was that he stays very well and I had to make my move first."
Outsider Ribchester was third, while Air Force Blue finished well off the pace under Ryan Moore, crossing the line second-last on the Rowley Mile, with O'Brien stating: "Perhaps I over-trained him, but ultimately no-one's died."