We are entitled at this point to feel that we've all been here once before. This time last year Harrington won the Irish PGA. Nobody paid much attention to him back then. Hardly a surprise there. He came in under the radar at Carnoustie because his earlier form had been so wretched.

So he beats some honest toilers in Ireland? So what. Where did he finish before that? Tied for 51st at the European Open. And before that? Tied for 54th at the Travelers championship in the States, a continuation of the wayward golf that saw him shoot 80 in his second (and last) round in the US Open a week earlier. Harrington was friendless in the betting markets a year ago. Not now, though. Twelve months on and we know better. The Irish PGA might be a dot on the golfing landscape but for Harrington it is more than a tournament, it's a launch pad.

The champion has been playing it cool of late. He's been talking psychology. If he wasn't a student before his Open win then he is now. He has seen how a major championship can change a golfer. The one he mentions is Angel Cabrera but, really, he could include other recent first-timers in that; Michael Campbell, Zach Johnson, Trevor Immelman, even Geoff Ogilvy to a point. Cabrera hasn't won a tournament since his US Open of 2007. Campbell and Johnson have only won once since they broke their ducks in 2005 and 2007. Immelman, though blighted by injury since winning the Masters in April, has been cut in 50% of his tournaments since then. Ogilvy, though impressively consistent, has also only won once since his US Open.

"I played with Angel Cabrera (at Torrey Pines] and I definitely felt there was extra stress on him because he was defending," says Harrington. "He was trying too hard, if anything. I don't want to go down that road of feeling that how I hit my tee shot on the first has any reflection on my win in 2007. I've tried to put Carnoustie to the back of my mind this year. I'm trying to downplay the significance of being the current champion. I'm trying to convince myself that, whatever I do the week of the Open, if I turn up and don't play well, they don't take the Open away from me. I'm still the Open champion from 2007. I don't have to go out and prove anything."

It's hard to know if he really feels that way or if he's just saying it in order to convince himself it's true. But nothing to prove? Honestly? It would be interesting to know if there is a small part of Harrington that thinks he got lucky at Carnoustie. There must be. After all, this is what he has had to say about that near-ruinous 5-iron approach to the 72nd hole that found the Barry Burn.

"You can't believe how many negative thoughts someone can come up with in the space of a few seconds. I'm devastated, I'm embarrassed, I can't believe I've messed up. I'm an idiot, I've just choked on one on the most important shots of my life in front of my family and friends and all those people. I'm spiralling down and down."

That he survived the horrors and is now considered a fine and deserving champion instead of the choker of his age, a title that would have stayed with him until his dying day, was decided by Sergio Garcia's missed putt in the first instance. Would Harrington have been able to face a golf course again had the Spaniard's putt dropped instead of staying up by a matter of an inch? It's a question Harrington has posed himself without ever coming up with a convincing answer.

Nothing to prove? Well, maybe just this: that he can win a major without imploding and without any help from anybody else.

All the Carnoustie questions are coming his way again. You can predict them. The emotion of it, the honour of it, the pressure of living with it, what it meant to Ireland, what it meant to young Paddy, the son who charmed the world when running on to the green on 18 after his father messed up and gave him the kind of adoring look that "made me think I was the champion" and what it would have meant to old Paddy, the dad who lost his battle with cancer a year earlier.

The process of trying to stay in the present is going to be a challenge. He knew this months ago. The student in him has observed the way other champions burned themselves out in the year after their breakthrough, playing everywhere they were asked, turning up at functions they'd no need to be at, all because of a naked pursuit of dosh or because they felt it was their obligation as a major winner. "I've made a special effort not to get caught in that trap, or so-called trap. You know, a lot of major winners are complaining a couple of years after they won that they played too much or tried to change so much. So I've deliberately kept the tournaments to as little as possible to stay as sharp and as focused as I can."

Good luck to Harrington this week in his efforts to downplay Carnoustie – we truly wish him well just as we long for the day that man can jump over the moon. He's right to try and rid himself of the burden of expectation, but it's out there and he knows it.

It's banging on his door, literally. He tells a story about his new reality, about his return to Dublin from the US Open, where he thought he played reasonably, and a conversation he had at home with a delivery man. To the guy with the parcels, 36th at Torrey Pines was a letdown. He wanted to know what went wrong over there. "What happened to you?" he asked. Harrington is now being judged by a whole different set of standards.

"That's where it's changed. Doesn't matter how many times you finish with a decent performance; if you're not winning you kind of get the feeling that you're not achieving or you're failing in some way. There is the extra pressure, no doubt about that."

He says he feels good now. Physically, he's never been better. His one concern is that he talks too much. "I get a little bit excited when I talk. I ramble on too much. Talking just drains me."

He's still good at it, though. No shutting Padraig up in the press room and there is a lot of Irish money hoping that there is no rival for him on the golf course either. His form in Wicklow was ominous. The champion has many duties to perform this week but, still, he seems well focused on the only one that really matters.