Odds-on favourite Kingman recovered from his surprise English 2,000 Guineas defeat to impressively win Saturday's Irish equivalent at the Curragh.
The John Gosden-trained colt was edged out by 40-1 shot Night of Thunder at Newmarket, but his backers scarcely had a moment's worry this time.
Sent off the 4-5 favourite, Kingman won by five lengths from Shifting Power (7-1), with Mustajeeb (4-1) in third.
The victory gave 26-year-old jockey James Doyle his first Classic win.
And this was a first Irish 2,000 Guineas triumph for Gosden and owner Prince Khalid Abdullah, as Aidan O'Brien was unable to land a fourth straight victory in the race after his main hope War Command was a late withdrawal.
Kingman moved smoothly into contention as the runners came over towards the near rail in the straight, and the response was immediate when Doyle pressed the button a furlong out.
The colt will now be aimed at the St James's Palace Stakes at Royal Ascot next month, when he could face a rematch with Night of Thunder.
"Two furlongs out, you could see he was cruising," said Gosden, who added Doyle had ridden "beautifully".
"He's a very talented horse and it's lovely to win a Guineas with him."
Teddy Grimthorpe, Prince Khalid Abdullah's racing manager, added: "He travelled really well in the race and did it pretty comfortably."
War Command was withdrawn from the race on Saturday morning after overnight rain led to a change in the going.