SOUTHPORT, England. - Padraig Harrington, playing one of the best rounds of his life, defied strong gusting winds to complete a successful British Open title defense with a commanding four-shot victory on Sunday.

After dueling for supremacy with overnight leader Greg Norman on the front nine, Irishman Harrington broke clear of the pack with birdies on Nos. 13 and 15 to tighten his grip on the coveted Claret Jug.

In glorious late afternoon sunshine at Royal Birkdale, the 36-year-old struck a majestic second shot with a five-wood to just three feet on the par-five 17th, setting up an eagle to put the championship beyond the reach of his rivals.

Harrington, whose title defense was in doubt at the start of the event because of an injury to his right wrist, made par on the last hole for a one-under 69, a three-over tally of 283 and his second major victory.

"I really felt good out there," a beaming Harrington said after covering the back nine in a four-under 32. "I hit the ball probably every bit as solid as I've ever hit it.

"Very few people have won back-to-back majors. Coming into this week I was trying to play that down but winning a second one does set you apart. There are less people in that club.

"It was a fantastic experience coming down the 18th knowing I had won the Open," added the Dubliner, who will rise to a career-high third in the world rankings.

Britain's Ian Poulter, helped by three birdies in the last 10 holes, also signed off with a 69 to secure second place at seven over, his best finish in golf's grand slam events.

Norman, bidding to become the oldest major champion at 53, had to settle for a tie for third at nine over after squandering a two-shot overnight lead and a one-stroke advantage with nine holes remaining.

The former world No. 1 bogeyed his first three holes en route to a 77.

"Obviously I'm disappointed," said Norman. "That would be an understatement if I didn't say I was disappointed. But it was a tough day today.

"Padraig played great. Even though he tried to let it get away in the middle of the round he came back and performed beautifully and finished like a true Open champion."

Level with Norman was Swede Henrik Stenson, who had a closing 71. With the wind gusting up to 72 kph, Harrington took advantage of playing partner Norman's stumbling start to forge two clear after six holes.

The Irishman made his first bogey of the day on the par-three seventh where he pulled his tee shot into the gallery left of the green from where he failed to get up and down.

He also faltered on the eighth, missing a par putt from four feet, and the ninth, where he missed a 10-footer, to trail Norman by one.

However Norman dropped his fifth shot of the round on No. 10 to rejoin Harrington in a tie for the lead before they were joined by Poulter, who coaxed in a 15-foot birdie putt on No. 16.

Norman's bid for one of the most remarkable achievements in sport began to fade as he bogeyed Nos. 12 and 13 before Harrington again regained control.