PÁDRAIG HARRINGTON'S mantra is that of the twin imposters, of the thin line between success and failure. Similarly, familiarity with a golf course can work either way: it can be an advantage knowing where the trouble waits, or it can intimidate you.

So while the two-time British Open champion believes that those who tee it up in the 90th US PGA championship at Oakland Hills and who happened to play in the 2004 Ryder Cup here have "a significant advantage" in the season's final major, first-time visitors such as Graeme McDowell will aim to take the view that what you don't know can't scare you.

McDowell has been a central part of the extraordinary season enjoyed by Irish players on tour. The unquestioned highpoint may have been Harrington's retention of the Claret Jug at Royal Birkdale just over a fortnight ago, but McDowell's graph, which has seen him rise to 31st in the world rankings following wins in the Ballentines Championship and the Scottish Open, is reflected in his belief that he isn't simply making up the numbers at the majors.

Indeed, if the 29-year-old Ulstermen were to aim to make a breakthrough win at any major, the US PGA is as good as any. In the 89 previous editions of this championship, no fewer than 31 players claimed it as their first - and only - major success.

McDowell, with his Ryder Cup ticket booked and his eyes focused on challenging for the European Tour moneylist, is aiming to follow on from a top-20 finish at Royal Birkdale, that could so easily have been much better, with an even stronger performance here.

To that end, McDowell intends to track down a DVD of the 2004 Ryder Cup and, also, to play practice rounds with members of that team - including Harrington and Darren Clarke - over the coming days as he prepares for his fourth appearance in the US PGA. His best result was tied-37th at Medinah in 2006.

Although McDowell could only manage a tied-56th finish in the Bridgestone Invitational - where Vijay Singh's one-shot win over Lee Westwood and Stuart Appleby moved the Fijian up to fourth in the world rankings and gave him a first win since the 2007 Bay Hill Invitational - the northerner admitted that much of his weekend was actually aimed at preparing for the challenge of Oakland Hills this week.

"I'm excited about this week. I hit it great in Akron. The previous week, I unscrambled my mind at home (in Portrush) by not doing too much and to get ready for the second part of the season, but I've learnt that my game is good enough (to contend in majors). I walked away from Birkdale with my second-best finish in a major and I walked away disappointed. I struggled with my game on Saturday there, struggled on the greens.

"But I've learned I can compete at this level, playing the best tournaments in the world against the best players in the world. I really feel my game's getting better."

Although he won the Scottish Open the week before Birkdale, McDowell believes his mindset heading in here is similar to what it was that week.

"I've the feeling that I have the game to compete," he claimed. "The short game is the key to the majors. The greens here are different to Europe and you've got to learn how to get the ball up and down on these fast greens. I was never at the business end (in Akron), so I used the weekend wisely, to work on my short game and get it sharpened up for here."

McDowell got his first look at Oakland Hills - a course once dubbed "the monster" by no less a figure than Ben Hogan - yesterday. The course has undergone more renovations since it last staged the US Open in 1996 and even since it played host to the Ryder Cup four years ago.

In 1996, it measured 6,974 yards but now it has been stretched to 7,395 (to a par 70). Designer Rees Jones lengthened 15 holes, narrowed several fairways, changed the depth, size and location of fairway bunkers on 12 holes and made changes to greenside bunkers on eight holes.

Despite the changes, Harrington believes players who competed in the Ryder Cup here will have an advantage.

"There was a lot of shots changed that week, from what we would have played in practice to what we played in the tournament. There's a lot of places you couldn't miss the pins, and only by playing competitively could you tell that . . . and we got that in. It had more to do with the lines (off the tee) and how the holes changed. I remember hitting the ball in the drain with a five-wood on the fifth and I got a rebuke from Bernhard (Langer) over that."

Since then, of course, Harrington has moved up significantly in status and will enter this week as one of the favourites. He is the second-highest ranked player in the world competing, behind only Phil Mickelson, and has been paired with Trevor Immelman and Angel Cabrera for the opening rounds.

McDowell has been grouped with Americans Ryan Moore and Billy Mayfair, while Clarke - who received a special invitation from the PGA of America to earn his place in the field, but who has moved back into the world's top-100 in 87th after his tied-sixth finish in Akron - will have Tom Lehman and Shingo Katayama alongside him for the first two days.

Mickelson, who won the 2005 title at Baltusrol, has been listed by William Hill as the tournament favourite at 10 to 1.

Singh, champion at Sahalee in 1998 and at Whistling Straits in 2004, is backed at 20 to 1.