SANDWICH, England -- Scotland may be the birthplace of golf but tiny Northern Ireland has become the centre of the game's universe.

Ulsterman Darren Clarke became the third citizen of that country to win a major golf championship in the last 13 months Sunday when he captured the 140th British Open by three shots over Americans Phil Mickelson and Dustin Johnson.

At the age of 42, Clarke's first major win comes at a time when he was believed to be on the downside of his career. At one time he was a top-10 player in the world but had slipped to 111th place heading into this Open.

Indeed, in his post-win press conference, Clarke playfully took a British writer to task for having written recently that Clarke was "on an inexorable slide into irrelevance."

"I guess this is a mirage," said Clarke holding the Claret Jug aloft.

"Truth is, I haven't given anybody much to write about for a long time. Bad times in golf are more frequent than good times and I've always been harder on myself when I fail. There have been times I've been completely and utterly fed up with the game. Friends and family have kept me going and that's why I'm sitting here right now."

Clarke acknowledged that he had received texts of encouragement from Tiger Woods Saturday night, but would not share Tiger's words.

"That's private," said Clarke.

Mickelson came from far back early in the final round to grab a share of the lead after seven holes, but Clarke quelled that uprising with a long eagle putt on the seventh hole. From there, Mickelson faded and Clarke marched largely unopposed to his first major championship after many disappointments, winning by three strokes at 5-under-par.

He joins reigning U.S. Open champion Rory McIlroy and 2010 U.S. Open champ Graeme McDowell as winners of three of the last five golf majors, all born and raised in Northern Ireland, a country of fewer than two million souls.

"I don't know why that has happened. We're blessed to have two fantastic players like Rory and G-Mac and I'm just the old guy who came along behind them," Clarke said. "We have fantastic golf courses and fantastic facilities but to have three major champions from such a small place in a short period of time is just incredible."

Now the country is preparing for a third celebration, with Clarke as the guest of honour this time.

"They're probably all having a drink in Portrush. I hope they are. Northern Ireland is a small place, a very close-knit community where everyone is pleased for our sporting guys that do well and I'm pleased to join them."

Mickelson began the day five shots behind, tied for seventh place, but made three birdies and an eagle on the way to a sizzling front nine of 30.

Mickelson's 25-foot eagle putt at the par-five seventh brought him level with Clarke. He then had another good look at birdie at the eighth that would have given him the outright lead but the putt lipped out.

When Clarke counter-punched with an eagle of his own at the seventh, he reclaimed the lead and never gave it up the rest of the way.

Mickelson began to fade with a bogey at the 10th. Then he missed a little, two-foot birdie putt at 11 and another seven-footer for par at the 13th.

"The putt on 11 was just a stupid mistake," said Mickelson. "Just a dumb mental error. It hurts to throw shots away when you're behind."

By the time he air-mailed his approach shot on the 72nd hole deep into the grandstand, Mickelson was an afterthought, five shots adrift of Clarke in third place.

"When I saw Darren wasn't going to make a mistake, I had to start trying to make birdies and that's when I started making mistakes," said Mickelson.

With the Claret Jug all but secured, Clarke bogeyed the final two holes to make the final result appear closer than it actually was.

Johnson started the day a shot back of Clarke at 4-under but dropped a shot on the front side. He birdied 11 and 12 to come within two shots of Clarke but when he hit his second shot out of bounds at the par-five 14th, the drama drained out of the proceedings and the official Royal and Ancient engraver was turned loose to enscribe Clarke's name on the Claret Jug.

After his eagle at the seventh, Clarke reeled off nine straight pars, safe in the knowledge that the only man who could beat him was himself.

And he wasn't about to let that happen. His only stumbles were a missed four-footer for par at the 17th, and a three-putt bogey at the last, as he raised his arms in triumph.