Padraig Harrington insists the Order of Merit would not be devalued if he failed to win it despite claiming back-to-back major titles this season.

Harrington became the first European since James Braid in 1906 to successfully defend the Open Championship at Royal Birkdale in July, and then won the USPGA Championship at Oakland Hills just three weeks later.

That would usually be enough to see the Dubliner top of the money list ahead of the season-ending Volvo Masters at Valderrama, which gets under way on Thursday, but the 37-year-old finds himself £230,312 behind Ryder Cup partner Robert Karlsson.

To claim a second Harry Vardon Trophy in three years, Harrington needs to finish first or second at Valderrama - a course he is not a particular fan of - and even victory would not be enough if Karlsson were to finish second.

But asked if it would take anything away from the Order of Merit if winning two majors in 2008 was not good enough, Harrington said: "Not at all. At the end of the day, I haven't played enough events to put myself out there.

"And in the events I played, I certainly didn't show the form that I probably showed in the States this year. My best events definitely weren't in Europe this year at all.

"I had a lot of top-five finishes in the States, but didn't seem to have much form in Europe, and that's why I'm not winning the European Order of Merit at the moment. Obviously, I need a big week this week.

"Robert has performed more consistently in Europe throughout the year, so consistency-wise, and that's what an Order of Merit is, he probably deserves it.

"But that doesn't mean he gets it. We have to wait until Sunday to sort that out."

Karlsson, 39, looking to become the first Swedish golfer to top the Order of Merit, has accumulated 12 top-10 finishes this season and also claimed back-to-back victories in the Mercedes-Benz Championship and Alfred Dunhill Links Championship either side of his second Ryder Cup appearance in Kentucky.

His performances in the major championships were also second only to Harrington, with eighth in the Masters, fourth in the US Open, seventh in The Open Championship and 20th in the USPGA Championship helping him amass more than £2million in prize money.

Lee Westwood and Miguel Angel Jimenez are also still in with a chance of finishing the year as European number one, although Westwood trails by £361,318 and even the second prize of £374,990 would need Karlsson to almost finish last.

Jimenez is £523,968 behind Karlsson and has to win the £562,485 first prize and also hope Karlsson finishes outside the top 20.

Other issues at stake include finalising the top 15 players on the Order of Merit who will secure a place in next year's US Open at Bethpage in New York, while the top 30 also qualify for The Open at Turnberry.