Kaymer admitted he had no visions of ever going that low in this tournament on this course. And he was so realistic after his opening charge at Pinehurst No. 2 that he offered a disclaimer.
"No one should really expect me to shoot another five under par the next three rounds," Kaymer warned Thursday evening. "I don't."
But then Friday morning, he got hot again. And stayed that way. Hole by hole, on a course so many other competitors were navigating as if it were a tightrope over the Grand Canyon, Kaymer skipped along. Carefree, confident, whistling while he worked. Thirteen pars, five birdies.
Lo and behold, another five-under 65 sent Kaymer to bed Friday night with an Open-record 36-hole total of 130 and a commanding six-shot advantage. That matches the largest lead ever enjoyed at this stage of the tournament.
Just as important, Kaymer finds himself in a mental zone — confident with his decisions, in a groove with his swing and not worrying about anything at all.
"It's quite nice to play golf that way," the 29-year-old German said with a modest shrug.
As has been well-documented, before the U.S. Open began, Kaymer was asked what 72-hole score he would be happy with. He threw out a gut-reaction answer: eight over par.
"I wouldn't take it anymore obviously," Kaymer cracked Friday.
Now he's attacking history. Rory McIlroy's 72-hole record of 16 under, set in 2011 at Congressional, appears within reach.
And don't rule out the possibility of Kaymer threatening Tiger Woods' 15-shot winning margin in 2000 at Pebble Beach, a record thought to be untouchable.
Late in his round, with an all-too-easy two-putt birdie on the par-five fifth hole, Kaymer became only the sixth player to reach at least 10 under at any stage of the U.S. Open.
And after two rounds in which only 13 of 156 players finished below par, Kaymer's onslaught left many of his peers in awe.
Kevin Na, for example, is tied for third with Brandt Snedeker at three under. Na feels like he has been dialed in. Then he surveyed Kaymer's assault on Pinehurst No. 2.
"I heard he played the No. 3 course," Na joked. "It's unbelievable what he's done. Was four or five under out there [through two rounds]? Yes. Was 10 under out there? No, I don't think so.
"I guess it was out there for him."
Sixty-seven players made Friday's cut, including Brendon Todd, alone in second at four under and paired with Kaymer in Saturday's final twosome. Among other notables in red figures, Dustin Johnson, Keegan Bradley and Henrik Stenson are at two under. McIlroy, Matt Kuchar and Jordan Spieth are in a group at one under.
But all agree this has become Kaymer's championship to chase.
On a course that has produced 1,430 bogeys or worse through two rounds, Kaymer has just one bogey. He has yet to three-putt. He ranks second in the tournament in fairways hit (25 of 28) and fifth in greens in regulation (26 of 36).
And the weekend stage shouldn't prove too big. Kaymer is already a major winner, having captured the 2010 PGA Championship. He held the world's No. 1 ranking for close to two months the following year. Last month, he scored an impressive victory at the Players Championship.
Now, with such a large cushion, Kaymer said he'll march forward without adding extra pressure to his weekend. He will guard against comparing his Saturday and Sunday efforts with his brilliant rounds on Thursday and Friday. He'll accept the inevitable string of bogeys he expects to come at some point.
"You just want to keep going, you want to keep playing," Kaymer said. "You want to challenge yourself. If you can stay aggressive and hit the right shots, that's quite nice that it's a battle against yourself."