Molinari defied the blustery conditions to post the only bogey-free round of the day, carding 16 pars and two priceless birdies, including the clincher at the final hole which earned him a two-shot win and his maiden major title at the age of 35.
The Italian’s composed performance earned him his third victory of a golden run of form which began at the BMW PGA Championship in May, while he also ended the American stranglehold on the major championships.
Tiger Woods and Rory McIlroy were among six players who had at least a share of the lead during an enthralling afternoon on the historic Angus links, but their challenges came up just short along with English pair Justin Rose and Eddie Pepperell.
Jordan Spieth’s bid to become the first back-to-back champion in a decade was ultimately scuppered by a double-bogey seven at the sixth and a cold putter throughout, and he would finish four off the pace after a 75.
But it was to be Molinari’s day in the limelight as the red-hot Italian avoided the card-wrecking mistakes that beset his fellow contenders, grinding out par after par and holing a series of clutch putts to keep himself firmly in the hunt.
He completed a full set of pars on the outward half to trail Woods by one at the turn after the 14-time major champion birdied the fourth and sixth to hit the top of the leaderboard and set the pulses racing among the record crowds for an Open at Carnoustie.
The Woods express then hit the buffers when he scrapped his way to a double-bogey six at the 11th and dropped another shot at the next, while Molinari continued his run of pars until breaking the streak with a nerveless two-putt for birdie at the long 14th.
Molinari’s excellent four took him to seven under and one ahead of an inspired McIlroy, who had struggled to the turn in an erratic 37 before he surged back into the reckoning with a birdie at 11 and a huge 60-foot putt for eagle at the 14th.
But McIlroy was unable to improve on six under and left a birdie putt short at the last to complete a 70 which gave him a share of the clubhouse lead with Rose, who had earlier birdied the 18th for the fourth consecutive day to return a 69, just two days after holing from 12 feet on the same green just to make the weekend.
With Spieth unable to recover from his front-nine mistakes, Xander Schauffele remained the biggest threat to Molinari as he recovered from an outward 40 with birdies at the 10th and 14th, where his 15-foot eagle putt hung on the back lip and refused to drop south.
However, Molinari’s nerve held on the 72nd hole as he hammered an arrow-straight tee-shot and clipped a sublime wedge to three feet before rattling in the winning putt and returning to the clubhouse to face an anxious wait to see if Schauffele could catch him.
But the 24-year-old American took himself out of the running with a bogey at the treacherous 17th, and he missed out on outright second when his birdie putt at the last lipped out on the right with Molinari in tears of joy in the winners’ enclosure.