On a windy final day at Royal Greens Golf and Country Club, the 40-year-old used all his experience to card a closing 70 and finish at 12 under, two shots clear of defending champion Dustin Johnson.
Raised in Northern Ireland and with a Major victory at Pebble Beach Golf Links in the 2010 U.S. Open Championship, McDowell is a master of playing in the wind, and he utilised all his guile to come home in 34 as many of his rivals faltered.
Johnson eagled the last in a 67 to finish a shot ahead of fellow American Phil Mickelson, Malaysia’s Gavin Green and Belgian Thomas Pieters.
McDowell’s 11th European Tour victory and first since making a successful defence at the 2014 Open de France takes him back into the top 50 on the Official World Golf Ranking and makes him a European Tour winner in three different decades.
The victory also means his 16 professional wins have come in 13 different countries and he is determined to have another prolonged spell at the top of the game after claiming his first triumph since turning 40.
“It’s special,” he said. “I’ve been working hard the last year and a half. I want to be back up there one more time just to be able to play against these guys.
“The game of golf is in such great shape, there are so many great players in the world, it’s so exciting to be a top player in the world and I want to be back up there again. I’m very excited that it’s happened a little faster than I expected but hopefully it’s laying some foundations down for having a big year.
“It’s been ten years since I won a U.S. Open, ten years probably since I played the best golf of my life. I feel like I’m moving back in the right direction.
“I have a solid team, life’s settled down. I’ve got a great wife and great family, I’m very happy with what’s going on in my life right now. I feel like the pond, the ripples in the pond have kind of steadied out a little bit now and I’m in a good place to play some good golf.
“Kevin (Kirk, coach) said to me, ‘There’s no reason why the best golf in your career can’t still be ahead of you’. I like that. I like that kind of idea. I like that focus.”
McDowell went left off the first tee to surrender an opening bogey and did well to save par on the third and fifth before holing an 18 footer on the par three eighth to get back to level for the day.
He found sand with his second shot at the ninth to drop back to 11 under and playing partner Victor Dubuisson was in a share of the lead with him at the turn.
The duo were in perfect sync at the 2014 Ryder Cup as they combined for two points out of two in the foursomes but they went in different directions on the back nine, with a Dubuisson double bogey on the 11th handing McDowell a solo lead he would not give up.
Pieters became his nearest challenger as he turned in 33 with birdies on the third, fourth and seventh and a bogey on the ninth.
The four time European Tour winner made back to back gains on the tenth and 11th and then bounced back from a bogey on the 16th with a birdie on the next, before pulling an eagle putt from four feet on the last.
When McDowell came up short of the 13th green and made a bogey, the lead was down to one, but he holed from 20 feet on the next and then hit a stunning approach to four feet on the 15th to give himself some breathing room and parred his way home.
Johnson had bogeyed the third but hit back with a brilliant chip-in eagle on the next before a birdie from four feet at the ninth moved him to nine under.
A bogey on the 13th left him with too much work to do down the stretch but his closing eagle saw him leapfrog the rest of the chasing pack.
Mickelson made a hat-trick of birdies from the second but would not make another until the last to go with a bogey on the 16th, while Green drove the green for an eagle at the 17th and also birdied the last to get back to level on the day.
England’s Ross Fisher eagled the last to finish at seven under alongside Frenchman Dubuisson, Spanish Major Champion Sergio Garcia, Mexican Abraham Ancer and Belgian Thomas Detry.
European Tour