Spain's Jon Rahm overturned a five-shot deficit with a brilliant final round of 62 to claim his second Dubai Duty Free Irish Open title in three years.
Rahm fired an eagle, eight birdies and two bogeys at Lahinch to finish 16 under par, two shots clear of England's Andy Sullivan and Bernd Wiesberger, the Austrian having the consolation of qualifying for the upcoming Open Championship.
Overnight leader Robert Rock also secured a place in the year's final major with a tie for fourth with fellow Englishman Eddie Pepperell and Spain's Rafa Cabrera Bello.
Paul Waring secured the final berth at Royal Portrush thanks to a birdie on the last in a closing 66.
Cabrera Bello had surged into a three-shot lead with three birdies in the first five holes, but started the back nine with four bogeys in six holes as Rahm piled on the pressure.
After covering the front nine in 31, Rahm birdied the 10th and holed from 25 feet for an eagle on the 12th before recovering from a bogey on the next with birdies on the 14th, 15th and 17th.
"I keep saying I love this tournament, I love the country, I love the people," said Rahm, who played the last 36 holes in 14 under after a 64 on Saturday.
"I feel like I'm at home every time I come here.
"I knew I had to do something amazing today to have a chance and that eagle on 12 got me going.
"My target was 15 under and I never thought I'd get to 16 under without a birdie on the last but I'm definitely thrilled with the back nine.
"I think Seve (Ballesteros) is the only Spanish player to have won this event twice so it's very special to add my name to the trophy again."