Shane Lowry celebrates winning the Open Championship golf tournament at Royal Portrush Golf Club in Ireland on Sunday. Photo: IC

Shane Lowry said that he "couldn't believe it was happening" as he marched down the 18th fairway in front of thousands of fans at Royal Portrush with the British Open title all but secured on Sunday.

The Irishman gave the home crowds a dream finish to the first Open to be held in Northern Ireland since 1951, as he saw off England's Tommy Fleetwood by six shots to win his first major title.

"I knew I was home and hosed down 18. I let myself enjoy it and it was incredible walking down 18, they were singing and going mad. I could not believe it was happening to me," said Lowry, after being serenaded with chants of "there's only one Shane Lowry" and "walking in a Lowry wonderland."

"I suppose I didn't even know going out this morning if I was good enough to win a major. I knew I was able to put a few days together. I knew I was able to play the golf course.

"I just went out there and tried to give my best. And look, I'm here now, a major champion. I can't believe I'm saying it, to be honest."

The 32-year-old, who took a four-shot lead into the final round, made four birdies as he carded a one-over-par 72 in wet and windy conditions to finish on 15-under for the tournament.

He is only the second player from the Republic of Ireland, after Padraig Harrington, to win the Open, and said it was always his dream to follow in his now good friend's footsteps.

"Look, I'm Irish. I grew up holing putts back home to win the Open. It was always the Open, wasn't it?" said Lowry.

"I watched Paddy [Harrington] win his two Opens. I didn't even know him back then. I'm obviously very good friends with him...

"Like you go into Paddy's house and the Claret Jug is sitting on the kitchen table, and I'm going to have one on my kitchen table, as well."

Lowry is projected to climb to a joint career-best ranking of 17th on Monday, but 12 months ago he slipped to world No.92 after missing the Open cut at Carnoustie.

He has since bounced back in style, also winning the Abu Dhabi Championship earlier this year and finishing tied-eighth at the PGA Championship in May.

"I sat in the car park in Carnoustie on Thursday, almost a year ago right to this week, and I cried," added Lowry.

"Golf wasn't my friend at the time. It was something that became very stressful and it was weighing on me and I just didn't like doing it. And, look, what a difference a year makes, I suppose."