Everybody in golf knows the old gag about Padraig Harrington: he couldn’t close out a big tournament and win. The Dubliner has finished second so often in his career that some had reached the conclusion that he did not have the stomach for professional golf in its most acute moments.

Not any more, not after Carnoustie’s final, dramatic minutes as the gloaming gathered on Scotland’s east coast last night. Harrington, at last, is a fulfilled man, after winning the 2007 Open in a way that maybe only the Irish can explain.

Coming to the 72nd hole with a one-stroke lead, Harrington did little to quell those who have questioned his nerve by dunking two shots into the Barry Burn en route to a double-bogey six. It left the Irishman enduring a four-hole play-off with Sergio García before finally lifting his prize. “Am I the Open champion? What does this mean?” an openly dizzy Harrington asked afterwards. “There are so many things going through my head right now.” It had been the moment — 6.29pm on Sunday, July 22, 2007 — that will define the rest of his life.

Harrington had finished in second place 30 times in tournaments, which is thought to be a European record. His 14 career wins, including two on the PGA Tour in the United States, had all stood in their own right, but finishing second so often had left the Irishman having to live with a peculiar type of stigma.

Even in previous majors, Harrington had seemed to flatter to deceive. He had finished fifth in two Open Championships, in 1997 and 2002, and had also finished fifth in the 2000 US Open and the 2002 Masters. Nobody doubted his talent — it was his nerve, his killer instinct, that people queried. Yet just days before this 136th Open, Harrington had provided a vivid clue about the state of his mind and game in an interview he gave to a golf reporter in Ireland. “I’m playing well and I know I am capable of achieving it [winning the Open], but one of the things I’ve had to try and learn throughout my entire life is how to play with confidence,” he said.

And then he added this: “At the moment I’m in that sort of place and it is good experience for me. My problem is I can see myself doing no wrong. I have no fear.”

Harrington, who has a degree in accountancy and a brain that would have sustained him in life beyond the fantasies of sport, had come to be seen as a talented but underachieving player in the ten years since he turned professional and joined the European Tour in 1996. 11 years ago a win came quickly in the Spanish Open, but a four-year hiatus developed before he won again. The doubting began.

The year 2000 was the season that fixed his ability — and his infuriating weaknesses — in the minds of golf fans. Harrington won twice, in Europe and in South America, but it was a ghastly run of seven second places in 11 months that left him being cast among the weak-kneed of European golfers.

Harrington has always been bravely open about his chronic battle to believe in himself, a theme he happily embarked upon again last night as he proudly cradled the Claret Jug.

For example, speaking of the three-foot putt on the final play-off hole that finally landed him this championship, Harrington said: “I hated that putt — it was two feet too long for me. In fact, it was three feet too long.”

Or even while talking about his whole life’s struggle to have faith in his ability, Harrington spared himself nothing while assessing the journey that has brought him to this moment. “People had far more belief in me than I had in myself,” he said. “The background to all this is that I only turned pro at 21 because there were other guys turning pro at the time who I had been beating and who I knew I could beat. But after that, I couldn’t believe it. I won after ten weeks and I just kept going. Like I say, I couldn’t believe it.”

There is a Scottish tint to this Irish celebration. Among those whom Harrington was keen to thank was Bob Torrance, the golf coach from Largs who always sounds as if he stores half a ton of gravel in his throat and to whom Harrington turned eight years ago to haul his game up to a new level.

On Tuesday evening, before he knew that he would be savouring this moment, Harrington spoke movingly and articulately about the influence Torrance has had on his career as the veteran coach was being presented with the Outstanding Services to Golf Award by the Association of Golf Writers.

There is a beauty in the timing of both these prizes, as first Torrance and now Harrington savour their feats.

Harrington highlights

1971 Born in Dublin on August 31.

1995 On third Walker Cup appearance is on the winning side at Royal Porthcawl against a United States team featuring Tiger Woods. Completes an accountancy degree before turning professional with a handicap of plus two and gaining his European Tour card at the qualifying school.

1996 Wins first professional tournament, the Spanish Open.

1997 Teams up with Paul McGinley to win the World Cup for Ireland at Kiawah Island.

1999 Makes Ryder Cup debut as Europe lose in controversial circumstances at Brookline.

2000 Has five-stroke lead going into final round of Benson and Hedges International but is disqualified when it is discovered he failed to sign his scorecard after the first round.

2001 Wins biggest title to date in the season-ending Volvo Masters.

2002 A key member of Europe team who regain Ryder Cup at The Belfry and has best year in the majors, finishing fifth in the Masters, eighth in the US Open and fifth in the Open, missing out on a play-off at Muirfield with a bogey on the 72nd hole.

2004 Helps Europe to retain the Ryder Cup with a record nine-point win at Oakland Hills.

2006 Wins Dunhill Links Championship at St Andrews and finishes joint second in the Volvo Masters at Valderrama to pip Paul Casey to the Order of Merit title.

2007 Wins first major title in the Open at Carnoustie after a play-off.