The 2010 US Open champion shot an even-par 70 at the Royal Greens Golf Club to givie him a two-shot win over defending champion Dustin Johnson
Graeme McDowell said he was "relieved" after successfully defending his overnight lead on a windy Sunday afternoon to win the Saudi International for his 11th European Tour title but first in nearly five-and-a-half years.
It was the 16th international win for the 40-year-old, who is expected to rise to inside the top 50 of the world rankings from his current 104th place.
"I didn't realise it had been quite that long here in Europe. I'm very excited. I'm very relieved," he said.
"It's been 10 years since I won a US Open, 10 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."
On Sunday at the Royal Greens Golf Club, the Northern Irishman had slipped to two-over par for his round with three bogeys in 13 holes.
He still had a one-shot lead, but things were looking tenuous for the Northern Irishman.
The 2010 US Open champion then poured in a putt from over 25 feet on the 14th hole for a birdie, and muscled his iron shot on the next from the rough to tap-in distance for a second successive birdie.
After pars on the next two holes, McDowell walked down the 18th with a two-shot lead.
He made a nervy par despite hitting a fantastic tee shot.
However, his even-par 70 took him to 12-under par overall, giving him a two-shot win over defending champion Dustin Johnson.
The American former world number one closed with a three-under par 67 and an eagle on the final hole –- his second of the day -– to finish solo second at 10-under.
Belgian Thomas Pieters had set the clubhouse marker for a long time after a round of 65 at nine-under par, where he was later joined by Phil Mickelson (67) and Gavin Green (70), who were eventually tied third.
McDowell could now be looking forward to a return to the Masters in April after a three-year absence if he can stay in the top 50 until the end of March.
Watch extended highlights of G-Mac's 11th Tour win on our YouTube channel.— The European Tour (@EuropeanTour) February 2, 2020
"My big goal this year was to be back in the top 50 in the world, back competing in the big tournaments," he said.
"I'm very excited that it's happened a little faster than I expected.
"It's a very important win, and hopefully one that I can really double up on and kick on from here. I'm excited to see how my schedule is going to develop from here.
"Called my kids right off the 18 green. They were jumping around the house. My little boy was shouting, 'Daddy, you won'. That's the kind of stuff I am excited about."
World number five Johnson was disappointed with his putting but satisfied that he was moving in the right direction after undergoing arthroscopic surgery on his left knee following the PGA Tour Championship in August last year.
"It was another day where it could have been a lot better. I'm pleased with the way I played, but I would have liked to give Graeme a little more pressure coming down the stretch," said Johnson.
"The game's in good form. It's only my second event since the Tour Championship, so I haven't played much golf. I feel like the game's starting to come around a little bit."
World number one Brooks Koepka could not make a move on the final day and a two-over par 72 after one double and four bogeys dropped him down to tied 17th at four-under.