The terrier-like University of South Florida star (22) birdied two of her last three holes to beat Scotland’s Lorna McClymont by two holes in the 36-hole final to become the first American winner since Kelli Kuehne in 1996.
She looked to be heading for a heavy defeat when she went four down after eight holes before she won four of the next six and headed to lunch with a one-up lead.
McClymont, a 23-year-old two-time R&A Student Series and two-time Irish Women’s Amateur Open winner, fell three down after 24 holes.
But she fought back to level the match with wins at the 25th, 28th and 32nd before going one up with three to play thanks to a brilliant birdie two at the 15th.
Green proved a class apart coming down the stretch, however, and her brilliant putting proved the difference.
As the rain abated, she got up and down from short of the 16th for a birdie four to level the match, reclaimed the lead with a par-four at the 17th and then closed it out with a sensational birdie three at the last.
Opting to put her driver back in her bag, she hit a stellar three-wood to the lower part of the fairway and followed it with a brilliant approach to 22 feet.
After watching McClymont miss her putt from 35 feet, she rolled in hers to take the title in her first appearance in the championship and head for next week’s Arnold Palmer Cup at Lahinch with a spring in her step.
“It’s awesome,” Green said after securing exemptions into the AIG Women’s Open, the Evian Championship, the US Women’s Open and the Augusta National Women’s Amateur.
“Lorna is an incredible player; every player that I faced put in great matches — like awesome.
“I don’t I don’t even know what you get when you win. I just know that there’s a big old trophy. This tournament’s pretty old. It’s got a lot of history. It’s incredible to have my name on that little trophy. It’s ridiculous.”
She added: “Ireland has been very good to me. Very, very good to me.”
She carried her own clubs throughout the week, even in the final when the rain was hammering down and she might have benefited from the extra help.
“To be honest with you, the reason I didn’t have a caddie was just because I didn’t have that much money to spend,” Green confessed. “But yeah, it just worked out.”