The Dublin star, who admitted he had struggled to cope with the weight of expectation from the partisan Irish Open crowd coming down the final stretch, had to go into and win a tense play-off against Bradley Dredge after the two had finished the final regulation 18 holes locked on 5-under 283 totals, Harrington having closed with a somewhat shaky 71, Dredge with a catch-up 68.

Harrington's dream triumph ended a 25-year wait for an Irish winner, finally matching John O'Leary's success at the Irish Open in 1982.

Harrington, 35, headed into the final day with a three-stroke lead, but by the 17th he had been caught at five-under by Welshman Bradley Dredge Dredge.

They could not be separated at the last so they returned to the 18th for a sudden death play-off which Harrington went on to win with a par five after his opponent's third shot plugged in the river bank guarding the green.

The Ryder Cup star held his nerve to get up and down from 28 feet, sparking wild scenes at the Adare Manor Hotel and Golf Resort.

"It is great. I'm starting to get emotional. Throughout the day I had to keep on a level keel and it is only now it is starting to hit home," said Harrington.

"It is the fifth biggest tournament for me to win. I can win the four majors and then my home open is the next biggest event for me."

Harrington admitted the passionate home fans had been both a help and a hindrance during a tense final round.

"I found it difficult today, no question about it. All the way through I was more nervous there then I had been in many a tournament and I had to work very hard to stay focused and stay calm," he added.

"But the atmosphere was great, they were absolutely fantastic. I bogeyed the second hole and the applause I got going to the third tee really gave me a boost, gave me a lift, and I went and birdied that one."

Back in 1982 O'Leary, who was at Adare for the finalo-day climax on Sunday, won £13,000 for his victory, less than the player finishing a lowly 46th this week will take home.

And he paid tribute to Harrington for matching his achievement.

"It's very appropriate for this great championship that Europe's number one should be the first Irish player to get a win since then," said O'Leary.

"I'm personally delighted Padraig won today. I've had my time, and they were very special times.

"For the people who have made this a great golfing country, they deserve a day out, it shouldn't be 25 years since [an Irish winner].

"It was very interesting; Padraig saying this week it was the fifth most important tournament to him.

"In my time I can vividly remember the significance of the event, it was that and the PGA Championship at Wentworth which had a different status outside of the Open championship.

"So it was the Open championship followed by the PGA and Irish Open in equal order. Probably that's to do with the people, the way they respond to the event is extraordinary."

Harrington got off to a shaky start when he fluffed a chip to bogey the second, but bounced back with a birdie on the next.

He bogeyed the fifth but then went birdie-birdie-eagle from the seventh - holing a 10-foot putt on the ninth - to move to seven under par.

A three-putt bogey at the 11th coupled with Dredge's birdie at the next halved the Irishman's lead, although that was extended to three strokes again when his Welsh playing partner bogeyed the 13th.

Dredge refused to throw in the towel, though, and chipped in from 20 feet for birdie at the next and then holed from 30 feet on the 15th to reduce his deficit to just one shot.

The Welshman looked to have let Harrington off the hook when he three-putted the 16th after an overly-cautious tee shot, but there was still time for more drama to come.

Dredge missed the 17th fairway, but fired a superb approach to three feet for birdie, while Harrington, from the middle of the fairway, missed the green and ran up a bogey five.

All square playing the last, both players made par fives to force a play-off.

Afterwards Harrington paid tribute to Dredge for giving him a real test.

"It was great the way the course was set up today because there were a lot of pins in bowls so you could make birdies," he added.

"He played great. He kept coming at me and kept making birdies and his birdie at the 17th was a body-blow and then I was just trying to keep a level head, which is difficult coming down 18 as it is a terribly tough tee shot.

"I feel sorry for Bradley but I'm sure there are plenty of wins ahead for him."

ALL THE FINAL ROUND SCORES

(Gbr & Irl unless stated, Par 72)

(Padraig Harrington wins at 1st extra hole)

283 Padraig Harrington 73 68 71 71 (£284,141)

283 Bradley Dredge 75 71 69 68 (£189,425)

287 Simon Wakefield 70 72 73 72 (£106,725)

288 Andres Romero (Arg) 68 74 75 71, Louis Oosthuizen (Rsa) 69 74 73 72, Richard Green (Aus) 71 73 72 72

290 Simon Dyson 68 78 75 69, Peter Hanson (Swe) 68 78 73 71, Francesco Molinari (Ita) 71 74 73 72, Raphael Jacquelin (Fra) 74 72 72 72

292 James Kingston (Rsa) 69 78 76 69

293 Jarmo Sandelin (Swe) 72 78 75 68, Alexander Noren (Swe) 74 75 75 69, David Lynn 72 75 76 70, Carlos Rodiles (Spa) 73 72 77 71, Marc Warren 76 73 73 71, James Heath 74 70 77 72, Christian Nilsson (Swe) 69 74 76 74, Gary Murphy 74 72 73 74, Damien McGrane 75 72 70 76

294 Miguel Angel Jimenez (Spa) 74 73 77 70, John Bickerton 75 74 75 70, Sandy Lyle 72 74 76 72, Oliver Wilson 73 75 74 72, Lee Westwood 71 77 72 74, YE Yang (Kor) 72 77 71 74, Phillip Price 72 73 74 75, Jyoti Randhawa (Ind) 76 70 73 75, Joakim Backstrom (Swe) 71 71 76 76, Alastair Forsyth 72 72 74 76

295 Graeme McDowell 74 74 77 70, Mark Pilkington 73 76 76 70, David Park 72 78 74 71, Michael Jonzon (Swe) 72 72 77 74 296 Martin Kaymer (Ger) 74 77 77 68, Mads Vibe-Hastrup (Den) 74 74 74 74

297 Soren Hansen (Den) 73 72 82 70, Rafael Cabrera Bello (Spa) 79 69 78 71, Stephen Gallacher 76 73 77 71, Richard Sterne (Rsa) 71 79 75 72, Mark Foster 73 77 75 72, Christian Cevaer (Fra) 75 75 73 74, David Higgins 75 70 76 76, Ignacio Garrido (Spa) 77 71 73 76

298 Simon Khan 71 79 77 71, Soren Kjeldsen (Den) 74 75 77 72, Ariel Canete (Arg) 72 75 78 73, Fredrik Andersson Hed (Swe) 76 75 74 73, Edward Rush 77 73 74 74, Maarten Lafeber (Ned) 75 75 72 76, Peter Gustafsson (Swe) 68 75 78 77

299 Gary Lockerbie 76 75 77 71, Mattias Eliasson (Swe) 74 74 77 74, Emanuele Canonica (Ita) 75 76 74 74, Brett Rumford (Aus) 80 71 73 75, Thomas Bjorn (Den) 75 73 75 76, Andrew Marshall 76 72 72 79

300 Sven Struver (Ger) 73 74 79 74, Chris Gane 76 75 75 74, Paul McGinley 72 76 77 75

301 Steven O'Hara 73 76 78 74, Steven Jeppesen (Swe) 72 74 77 78

303 Christopher Hanell (Swe) 74 77 79 73, Alexandre Rocha (Bra) 70 81 77 75, Thomas Levet (Fra) 74 76 77 76, Martin Erlandsson (Swe) 76 72 76 79

304 Gary Orr 76 75 79 74, Jean-Baptiste Gonnet (Fra) 75 74 74 81

305 Matthew Richardson 79 72 79 75, Shiv Kapur (Ind) 77 74 79 75, Kenneth Ferrie 74 75 80 76, Matthew Zions (Aus) 71 78 80 76

307 (x) Pat Murray 76 72 79 80

314 Peter Hedblom (Swe) 75 74 82 83

(x) denotes amateurs