PINEHURST North Carolina (Reuters) - Martin Kaymer's stunning form over the first two days at the U.S. Open left his challengers trailing in his wake on Friday, reviving memories of runaway wins by Tiger Woods and Rory McIlroy.
The ice-cool German, oozing confidence since his victory at the elite Players Championship last month, has so far mastered a tricky Pinehurst layout, successive rounds of five-under-par 65 putting him six strokes in front in record fashion.
While Kaymer has been almost error-free in posting a record tournament low of 10-under-130 after 36 holes, he himself and many of his closest pursuers know that nothing can be taken for granted over the last two rounds.
"Certainly his game is on, he's putting incredibly well, driving it very well and playing great," British Open champion Phil Mickelson said of Kaymer, a former world number one.
"You never know what will happen in a U.S. Open. We have always had crazy things happen. There's a lot of guys right there ready to pounce if he slips up."
Mickelson, still hunting his first U.S. Open title after suffering the heartache of a record six runner-up spots at the event, will not be one of them after struggling to a three-over 73 on Friday that left him a distant 13 shots off the pace.
However 2011 champion McIlroy is a little closer, trailing Kaymer by nine after carding a 68 in the second round.
"I would like the rain not to come and for the course to get as firm as possible because Martin hasn't really seen it like that," McIlroy said of a Pinehurst layout that has played a little easier than expected due to softened conditions over the first two rounds.
"Over 36 holes, you never know what can happen but Martin's a good front runner and I can't see him sort of letting up."
McIlroy held a six-stroke lead after 36 holes in the 2011 U.S. Open at Congressional before going on to triumph by a record eight shots and he rates Kaymer's performance at Pinehurst, so far, as superior.
"What Martin's doing is more impressive than what I did at Congressional, just because of how difficult the golf course (here) is," said McIlroy, a double major winner.
"There's trouble lying at every corner at any missed green. Congressional was a little more benign than this is, a little softer, a little more receptive."
Kaymer, who landed his first major title in a playoff for the 2010 PGA Championship, would like to see conditions become more difficult at Pinehurst over the weekend.
"I would like to see it as tough as possible," said the 29-year-old from Dusseldorf. "I was always a fan of a golf course where you need to hit good golf shots and not really have a putting competition."
While Kaymer has been delighted with his form and course management so far at Pinehurst, he has no intention of setting himself a target for the last two rounds.
"I don't need to set any goals," he said. "I just wait for what the afternoon will do.
"If you set goals, then you're adding a little pressure because you try to reach them instead of going out there and being neutral, just playing. So I'm not really into goals for the next two days, I just want to play."
Asked what a second major win would mean to him, Kaymer replied: "In my books, I won a second major already with the Players. It's a career goal to win first to win one major. Fortunately I got that done fairly early in my career.
"By the end of your career, it comes down to the big, huge moments where you could handle the challenges. And it comes down to winning majors, World Golf Championship events, being on the Ryder Cup team, like those things.
"Obviously if I could win a second, third, fourth major, whatever it's going to be, it would be very, very satisfying. But after 36 holes, anything can happen over the next two days. We'll see."
Reporting by Mark Lamport-Stokes; Editing by John O'Brien