The Irishman was given a helping hand, mind you. Geoff Drakeford, the Australian who had led from day one and was six shots clear of Moynihan with 18 holes to play, stumbled over the finishing line and his five-over 75 led to the title slithering out of his clutches.
Moynihan's closing three-under 67 hoisted him to the top with a five-under aggregate of 275 and eventually gave him a two-shot triumph but it was his spirited recovery from that calamitous quintuple bogey on the 12th hole of the morning's third round that put an added layer of sheen to this unexpected success story.
Everything that could go wrong did go wrong. There was a wayward drive, two penalty drops and the inevitable three putt as he endured, what he called, "the worst hole ever". The fact that he immediately bounced back with a brace of birdies at the 13th and 14th, before making a further gain on the 18th in a battling 68, spoke volumes for his resolve in times of golfing crisis.
His hopes of winning the event remained remote, however. "I thought it was all over after that to be honest," said Moynihan, who became only the second Irishman, after former Ryder Cup player Philip Walton in 1981, to claim the crown.
Golf is a funny old game, though. Moynihan, who won the Irish Open Strokeplay in 2012 and represented GB&I in last season's Walker Cup, marched out in the final round and made some significant strides as Drakeford, who was four ahead of his nearest rivals after 54 holes, began to toil. Despite slipping to back-to-back bogeys at the seventh and eighth, following three successive birdies, Moynihan delivered a telling blow on the 14th where he launched a raking 7 iron into eight feet and holed the eagle putt. That gave him the clubhouse lead and a struggling Drakeford would not knock him off it.
The 22-year-old carded a double bogey on the 12th and then had to take a penalty drop from a bush on the 17th as the haemorrhaging continued. Another bogey on the last, after his approach had found the sand, brought the sorry episode to a close. "I hit a couple of stray shots and paid the price," he lamented.
Drakeford eventually had to settle for a share of second place on 277 alongside Huddersfield's Nick Marsh and Irishman Jack Hume, who both closed with four-under 66s.
On the home front, Scott Gibson, the Southerness youngster, was the pick of the bunch in an event that has not had a Scottish winner since 2008. Gibson posted final-day rounds of 73 and 72 and shared seventh on a tally of 281.