The 17-year old boys’ international from The Island closed with rounds of 76 and 75 to win by a stroke from 20-year-old Dutchman Robin Kind on seven over par 295.
And he did it in style, firing a 198-yard three wood into the teeth of the wind to five feet at the 17th to set up a championship winning birdie.
Kind bogeyed the 18th for a 75 to set the clubhouse target at eight over 296 but Moynihan, who came into the championship with form having joined Lee Westwood and Justin Rose on the list of winners of the prestigious Peter McEvoy Trophy for under 18’s at Copt Heath last month, held up under pressure.
Needing a bogey at the last to win, he found the fairway with a three wood, steered his four iron approach left of the green, horse-shoed out from 10 feet for par after a good pitch and sweetly tapped in from six inches to win the blue riband title in Irish amateur golf.
“It’s just amazing,” Moynihan said after a final round featuring five bogeys and two bogeys. “I don’t know what the wind was gusting to but it was seriously tough and my short game saved me on the back nine. I’m absolutely thrilled with the win.
“That’s probably the best two rounds of putting I have had for a while. I’ve hit drives 350 yards and 220 yards today. It was just one of those days where you had to grind it out.”
The Irish boys’ international went into the final round tied for the lead with Stackstown left-hander Richard Bridges on four over par with 20-year old Dutchman Kind a shot further back.
But as Bridges was blown away on a cruel southwest wind that gusted over 40 mph at times, shooting 84, Kind and Moynihan emerged as the true title contenders on a day of high winds and high drama.
The Irishman eventually clinched victory by the narrowest of margins on seven over par 295 thanks to a wonder shot at the penultimate hole that momentarily gave him a one stroke lead until Kind bogeyed the last.
“The 17th was the key,” Moynihan said. “The tee was up and the bunkers were in play but I hit a good drive and bulleted a three-wood from 198 yards into the teeth of the wind to five feet and rolled in the left to right putt.
“I knew walking up to my chip shot at the last that I could take three from there and win. The back nine was just brutal and I am just delighted to have held up.”
Scoring soared in the morning despite the fact that the GUI took the precaution of shortening the course by around 125 yards.
Belvoir Park’s Harry Diamond — who led by a stroke overnight from the Moynihan, Kind, Dutchman Daan Huizing and American Mike Miller — carded rounds of 81 and 76 to finish sixth on 12 over.
Headfort’s Brian Casey, who won last week’s Munster Strokeplay at Cork by 10 strokes, closed with rounds of 74 and 72 respectively to set the clubhouse target at 10 over par but was forced to settle for third place in the end as Moynihan weathered the storm.