Only Tiger Woods can have a pair of US Open titles to his credit and still have to defend his lack of success in the event.

Of his 12 major titles, just two have come from this particular championship and the most recent was at Bethpage five years ago, two years after his first at Pebble Beach.

He spurned a good opportunity for title number three at Pinehurst in 2005 and missed the cut at Winged Foot last year, when he was still mourning the death of his father, Earl.

But ahead of his 13th US Open appearance at Oakmont today, Woods had no problem when asked to justify his record.

''I think I've had pretty good success, I've won two,'' he said.

''It's not an easy championship. It's probably the most difficult championship that we face all year.''

Phil Mickelson, for one, would love the opportunity to explain away a mere two US Open victories. The left-hander has four runner-up finishes in the event to his name since 1999 and, though he has broken his Major hoodoo in recent years, question marks still remain in this event.

Those doubts have grown since his infamous last-hole meltdown last year, an experience Mickelson is using as inspiration.

''I don't ever want to put it totally behind me,'' said the American, who had been a doubt for Oakmont with a wrist injury.

''I want to look back on it and recall what happened because I used that analysis to design a game plan to start driving the ball better.

''If I just forget about it, I'm not taking advantage of the opportunity to take some weaknesses and hopefully turn them into strengths.''

Driving off the tee will be key over the next four days. It is thought to be next to impossible to stop the ball on the greens when playing from the rough.

Woods said: ''I hear that you should be able to get a five-iron on the ball in the first cut. I have yet to be able to experience that.''

Oakmont is considered so difficult, some have said this week the only winner will be the course itself.

Predictions of the winning score have ranged from even-par all the way up to ten-over.

Ireland's Padraig Harrington said: ''You kind of come to expect, at a US Open, that you're going to come to a very difficult golf course.

''This one has been built up as being tougher than the rest. It does make Winged Foot seem very pleasant.''

Last year's event was won with a score of five over, and protecting par also appears to be the US Golf Association's sole concern this time around.

The 7,230-yard Oakmont has been designated a par 70. It features the longest hole in US Open history, the 667-yard par-five 12th, one of only two par-fives on the course.

Whether the winner is able to finish in red numbers this year is not totally in the players' hands, according to Harrington and Woods.

Harrington said: ''If the USGA wants us to shoot level par this week, the winning score will be level par.

''It's much more in their control than it is in any player's control.''

Woods added: ''It's fantastic. The golf course is without a doubt difficult, we all know that, but it's fair.

''We have to see what happens with pin locations. If they go crazy on pin locations they can make it impossible.

''But if they put pins in generous spots then I think it will just be a fantastic test."