How do you top winning your national Open as an amateur? In Shane Lowry's case by winning the Open Championship in front of a raucous sell-out crowd at Royal Portrush.

The fact that Lowry is from Offaly in the Republic of Ireland, rather than Northern Ireland, could not have mattered less as the 32-year-old became the fifth Irishman to lift the Claret Jug after Fred Daly, Padraig Harrington, Darren Clarke and Rory McIlroy.

Clarke, McIlroy and Portrush native Graeme McDowell had carried the hopes of those dreaming of a Northern Irish winner of the first Open staged outside Scotland or England since 1951, although only McDowell made the cut.

"Those guys are from here," Lowry acknowledged after his stunning third round of 63. "I grew up four hours away. I kind of felt like I could come here and come under the radar a little bit, that's what was nice about this week. But obviously I'm not quite under the radar any more."

Talk about an understatement.

Lowry was of course widely known before the Open, the son of All-Ireland winning Gaelic footballer Brendan Lowry and a four-time European Tour winner who hit the headlines for winning the 2009 Irish Open as a 22-year-old amateur.

After beating Robert Rock in a play-off – Rock walking away with first prize of 500,000 euros which Lowry could not accept – Lowry turned professional and missed the cut in his first three events in the paid ranks.

"I think my first pay cheque was 16,000 euros from the French Open and the first thing I did was I went home and gave my granny 500 euros because she always looked after me when I was younger," Lowry recalled.

It took until 2012 for Lowry to win his first European Tour event as a professional in the Portugal Masters and another three years before a first World Golf Championships success at the Bridgestone Invitational.

A maiden major victory looked on the cards the following year when Lowry took a four-shot lead into the final round of the US Open, only to struggle to a closing 76.

After completing a third round of 65 on Sunday morning due to previous weather delays, Lowry had seven hours to kill before the final round – "Those few hours were tough. I was restless, I tried to go for a kip and couldn't sleep" – and started by dropping four shots in the first 10 holes.

At that point he was two shots behind eventual winner Dustin Johnson, although he was effectively back in front when he birdied the 12th and Johnson bogeyed the 14th as the American would eventually be penalised a shot for causing his ball to move when addressing a par putt back on the fifth.

However, Lowry then three-putted the 14th, 15th and 16th to end his chances of becoming the first player from the Republic of Ireland to win the US Open, but left Oakmont convinced he had what it takes to win a major.

"I'm bitterly disappointed but I'm definitely good enough to win one of these," Lowry said. "It's great to be in the position I was in and I hope I get myself in there quite a few times."

The prospect of that happening at Portrush, where Lowry won the North of Ireland Championship in 2008, looked slim after a few days of indifferent practice, but a 40-minute pep talk from long-time coach Neil Manchip over a cup of coffee worked wonders.

Back-to-back rounds of 67 were followed by that brilliant 63 and Lowry was on his way to seeing his name etched onto the Claret Jug, not far from that of his golfing hero and three-time major winner Harrington.

"I'm quite friendly with him now and it's great to be able to feed off someone like that," Lowry said. "If I can go on and achieve even half of what he's done I'd be happy enough."

Half of three majors will be tricky to achieve, but a third is not a bad start.