Padraig Harrington defied strong gusting winds to complete a successful British Open title defence with a commanding four-shot victory on Sunday.

After duelling for supremacy with overnight leader Greg Norman on the front nine, Irishman Harrington broke clear of the pack with birdies on 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 utility wood to just four feet at the par-five 17th, setting up an eagle to put the championship beyond the reach of his rivals.

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

"With a four-shot lead after eagling 17 I knew I had won," a beaming Harrington told BBC television after covering the back nine in a four-under 32.

"It was an enjoyable 18th hole. I did want to shoot 69, or in the 60s, for posterity.

"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. This week was worth everything."

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.

Australian 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 number one, who has triumphed only once in eight attempts when holding at least a share of the 54-hole lead in a major, bogeyed his first three holes en route to a 77.

"At the end of the day Padraig did a tremendous job and is a deserving champion," said the Australian. "I enjoyed the week but I am disappointed at not getting it done."

Level with Norman was long-hitting Swede Henrik Stenson, who carded a 71.

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

However Norman dropped his fifth shot of the round at the 10th to rejoin Harrington in a tie for the lead before they were joined by Poulter, who coaxed in a 15-foot birdie putt at the 16th.

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

The Irishman, who won last year's title at Carnoustie in a playoff with Sergio Garcia, struck a superb five-iron approach to 15 feet at the par-four 13th and sank the putt to edge one ahead.

Another birdie followed at the 544-yard 15th where Harrington reached the fringe of the green in two and two-putted to double his lead, prompting a celebratory fist pump.

After parring 16, he eagled the 17th with one of the best shots of the championship before signing off with a par at the last to emulate Tiger Woods [Images], in 2006, with back-to-back Open titles.