Trading Leather claimed the Dubai Duty Free Irish Derby for trainer Jim Bolger, 21 years after the great St Jovite, giving jockey Kevin Manning his first success in the race.
The 6-1 chance travelled noticeably well throughout the mile-and-a-half contest and knuckled down well in the final furlong to get the better of Galileo Rock.
Festive Cheer came from last to grab third, but Epsom Derby one-two Ruler Of The World and Libertarian were both bitterly disappointing.
Ruler Of The World finished a never-nearer fifth, while Libertarian finished even further back.
Ruler Of The World was unsurprisingly a warm order following his impressive Epsom display, sent off a 4-5 favourite to give trainer Aidan O'Brien an 11th Irish Derby victory.
However, he was being ridden along towards the rear of the field rounding the home turn and while he made up some ground in the straight, he never looked like landing a significant blow.
The Elaine Burke-trained Libertarian, purchased by Godolphin since his excellent Epsom effort, ran even more disappointingly, with William Buick eventually easing down and beating only one home.
Last of all was Patrick Prendergast's Sugar Boy, another horse who has changed ownership this week.
Trading Leather had chased home Libertarian in the Dante Stakes at York and finished third in the Irish 2000 Guineas, before winning a Listed race at this track three weeks ago.
Never too far off the pace, he showed a good attitude when it mattered to beat David Wachman's Epsom third Galileo Rock, handing Bolger a second Irish Derby win following the victory of St Jovite in 1992.
O'Brien's apparent second string Festive Cheer could be counted slightly unlucky in third, flashing home after encountering traffic problems.
Manning, a leading jockey for several years, was delighted to finally break his duck in Ireland's premier Classic.
Manning said: "I was a bit afraid of getting to the front too soon. He gallops and he has pace.
"It means an awful lot to me to win this race. I missed the chance before when New Approach was taken out late on."
Wachman was delighted with the effort of the runner-up.
He said: "He ran well. The winner won well but we made of a race of it and I'm very happy with that.
"He's definitely stepped forward (from Epsom). These three-year-olds need to step forward through the year and he'll need to step forward again from here.
"Jim's horse travelled particularly well, we stayed on but I think the winner won with bit up his sleeve."
Asked whether Galileo Rock could be targeted at the St Leger, Wachman said: "He'll be in it, we'll see nearer the time. Good ground is essential and I think he'll really come into his own as a four-year-old."
O'Brien could offer no immediate reason for Ruler Of The World's lacklustre effort and could give the colt a break now.
He said: "He's had three quick enough runs. He was a bit warmer than he was at Epsom, but I don't want to make excuses as the winner did it well.
"We may give him a break now, he deserves it."