What makes Padraig Harrington the most intriguing as well as the most successful golfer at present is the way he has changed in the past few years. He remains an engagingly loquacious and charming Irishman, with a ready smile, who is prepared to talk to anyone. But almost without anyone noticing he has altered his thinking and his body - the way he talks and his golfing skills - and as a result has won three of the past six major championships, the latest coming on Sunday in the US PGA Championship at Oakland Hills, Michigan.

Harrington's change has been the greatest makeover in European golf since Nick Faldo in the mid-Eighties. Faldo had won more than a dozen events worldwide before, late in 1984, he started a two-year rebuilding programme after which he won six major championships.

This is what Harrington has done:

Approach

The influence of Bob Rotella, the noted sports psychologist, is revealed in the way that Harrington rarely says anything negative. He even managed to make a positive out of his two poor holes at the end of his round on Friday when he pushed a drive well wide on the 8th, his seventeenth hole, and then pulled an iron shot 40 yards left of the green on the short 9th. “I was probably the only man happy to finish bogey, bogey and think I had done well,” he said

He was positive about those shots later because by then he had come up with a reason as to why he had hit them. It was because he was dehydrated. Taking care not to be in that physical state again, Harrington played his last two rounds in 66 and 66 to emerge victorious.

Most players would want to forget finishing bogey, bogey, bogey in a major championship, as Harrington did in the the 2006 US Open. “Even though I finished with three bogeys, I played awesome for the first 15 holes at Winged Foot,” he said. “I walked off the 18th green and said to Bob Rotella, ‘Now I know I'll win a major.'”

Fitness

Looking at old photographs of Harrington, it is noticeable that he was heavier than he is now. Most people get fuller in the face and rounder in the waist as they get older. Harrington has a gym in his house and as a result of unusual dedication to physical conditioning, he is slimmer, lighter, fitter and stronger in the core muscles of the body than he was ten years ago.

Skills

He is now reaping the reward of ten years of exceptionally hard work on his swing. Under the eye of Bob Torrance, Sam's father, Harrington dismantled his swing and slowly began altering it to a more professional-looking one that is more repetitive, powerful and reliable under pressure. “I've been saying for three years now, I've done my practice,” he said. “I have spent ten years working all hours on my swing. Now I am here to play major championships.”

Mental approach

Harrington says repeatedly that he is best when he is up against it. “It has always been a part of my game: the worse situation you put me in, the better I get,” he said. “I play a lot of my golf with fear.”

If he does not have a concern, then he often invents one or exaggerates one to help him to focus and give him something to battle against. “I have always been good backed up against the wall,” he said.

The injury to the right wrist suffered on the Saturday before last month's Open Championship was so bad that he could not complete a practice round on the Tuesday and yet he was able to play without pain a couple of days later in the Open. At Oakland Hills, he said repeatedly that he was suffering a hangover from his Open success and was not swinging well during his first 36 holes. This helped him to change things so dramatically during the 28 holes he played on Sunday. His improved mental approach has resulted in him playing faster, too.

Desire to win

“Most guys who had won two in a row would be on cloud nine and would play great golf for the next six months,” he said. “I will be fighting it the next time I play. The “Paddy Slam”? I am the only guy who can go and win the next two, so yes, I am in position to win the “Paddy Slam”. That is all I can say.”

Confidence

Not long ago Harrington was a serial runner-up. Now he has become a serial winner. Such is the change in his confidence that the golfer who looked nervous on the last hole at Carnoustie in the Open in July 2007 now says that he relishes being in the thick of it approaching the end of a major championship.

“You get chances in a major tournament on the back nine and you have to take them,” he said. “I believe in taking responsibility whether you win or lose. I love the feeling that it is going to come down to the back nine and who can do it under pressure. I love it so much, I am disappointed I am seven months away from another major championship. I don't know what I'm going to do.”