His smile got wider with every hole coming in. The cheers got louder.

When his approach to the 18th was just on the fringe, he stretched out his arms and hugged caddie Bo Martin, whom Lowry had leaned on with brutal honesty.

"He was great at keeping me in the moment," Lowry said. "I kept telling him how nervous I was, how scared I was, how much I didn't want to mess it up. All I could think about was walking down 18 with a four- or five-shot lead, and lucky I got to do that."

The loudest roar of a raucous week was for a tap-in par that made Lowry a major champion.

"He's done brilliantly," Lee Westwood said after grinding out a 73 to tie for fourth. "All the chasers would have wanted tough conditions and he's clearly played brilliantly to be on the score he has, under the pressure he's under."

Fleetwood, the only player who kept Lowry in range, had chances early to put more pressure on Lowry. He missed a 10-foot birdie putt on the opening hole when Lowry still had work left for bogey. Fleetwood missed a 5-foot par putt on the third and his hopes ended from a bunker and the rough that led to double bogey on the 14th.

"I never really got close enough, and Shane played great," Fleetwood said.

Tony Finau shot 71 to finish alone in third, though he was never closer than seven shots. Brooks Koepka, going for his fourth major in the last seven, began the final round seven shots behind and opened with four straight bogeys. He shot 74 and tied for fourth.

Royal Portrush last hosted the British Open in 1951, the only time it had been outside Scotland and England. It pinned hopes at the start of the week on Rory McIlroy, who missed the cut by one shot. It celebrated Darren Clarke hitting the first tee shot Thursday. The other Ulsterman, Portrush native Graeme McDowell, basked in the loudest cheers he has heard this side of the Ryder Cup when he walked up the 18th green on Sunday.

And then along came Lowry, who teamed with McIlroy to bring Irish golf a European Amateur title in 2007, and who won the Irish Open as an amateur 10 years ago. He joins Padraig Harrington as Irishmen to win majors, while McIlroy, McDowell, Clarke and Fred Daly are major champions from Northern Ireland.

"Everyone knows we're all one country when it comes to golf," Lowry said.

It was one big group hug when it ended, starting with his wife and daughter, and his parents. Harrington and McDowell were among those waiting behind the 18th green to share in the celebration, along with Koepka and his caddie, Ricky Elliott, once a promising amateur who grew up at Royal Portrush.

"I didn't feel great out there. It was probably the most uncomfortable I've ever felt on a golf course," Lowry said. "You're out there trying to win an Open in your home country, and it's just incredibly difficult."

It showed early when Lowry pulled his tee shot into the rough, hit into a deep bunker well short of the green and had to make an 8-foot putt just to escape with bogey. The wind was picking up and it was relentless for so much of the day. Lowry made his move on the more forgiving holes early with three birdies in a four-hole stretch through the par-5 seventh that boosted his lead to six.

And then he held on.

J.B. Holmes, who shared the 36-hole lead with Lowry until falling back Saturday, really went the wrong direction. He hit his first tee shot out-of-bounds. And it only got worse. He made one birdie and shot 87.

Lowry finished at 15-under 269 and earned $1.935 million.

He shared his greatest moment with his family who paved the way, the players who inspired and encouraged him through the lows. And after he was introduced as "champion golfer of the year," he shared it with thousands of people he didn't even know, all of them crammed along the hillocks and swales, along the edge of the ocean, and who sat in the horseshoe-shaped grandstands on the 18th under umbrellas waiting for the Irishman to arrive.

Holding up the claret jug, Lowry said to them, "This one's for you."