Grey Swallow got the better of Vodafone Derby hero North Light to claim the Budweiser Irish Derby at the Curragh today.
The Dermot Weld-trained colt, ridden by Pat Smullen, took up the running from North Light in the final furlong and just held on by half a length, while Tycoon delivered a late challenge to finish third.
John Gosden's Day Flight was a non-runner in the race due to the good to firm ground.
The 10-1 winner was settled in the pack by Smullen as Moscow Ballet set the pace, with the Epsom second Rule Of Law sitting on his heels.
Kieren Fallon kept 8-11 favourite North Light handy in about fourth place throughout, but he looked unhappy with the easy pace and started to make a move on the outside six furlongs out.
As the leading duo began to fade, North Light was in front three furlongs out but Smullen was biding his time in behind and struck with a furlong to go.
The 150-1 outsider Tycoon put in a late run to snatch third from Rule Of Law, who beat the Epsom third Let The Lion Roar home once again.
Gosden's other runner, Percussionist, was always struggling towards the back and he dropped right out turning for home to finish last.
Grey Swallow had been beaten in two Classics earlier this season, finishing fourth in the English 2000 Guineas and third in the Irish equivalent, and this was his first attempt at further than a mile.
Weld said: "I've always believed in this horse. There were doubts about him staying a mile and a half, but he worked superbly the other day and I knew I had him in good form.
"This was a very good Derby and an extra special win as he was bred by my mother, who also owns part of him."
Smullen said: "I can't believe it. We had so much faith in this horse in the English and Irish Guineas, but obviously all he wanted was a little bit further. He's a champion.
"Words can't describe this. I've had an up and down year so far, but winning races like this is what it's all about. For the boss as well, and all the boys at home. It's unbelievable."