PINEHURST, N.C. -- Before he began his two-day assault at Pinehurst No. 2, before he charged into the U.S. Open record book with the lowest 36-hole score in the tournament's 114-year history, Martin Kaymer of Germany was asked what he thought the winning score would be after playing a practice round.

"I said 8-over par," Kaymer said.

After shooting 65 for the second day in a row and opening a record-tying six-shot lead at 10-under 130, Kaymer knows he needs to adjust his prediction.

"I wouldn't take it anymore, obviously," he said.

Tiger Woods might be missing from the U.S. Open championship, but you would never know it by the way Kaymer is playing. He's doing his best impression of the 14-time major champion by beating up on the field at Pinehurst No. 2 in Tiger-like fashion.

After opening with six birdies and only one bogey in the first round when he posted the lowest score in U.S. Open history at Pinehurst No. 2, Kaymer matched that with a bogey-free 65 Friday to break Rory McIlroy's 36-hole scoring record of 131 set at par-71 Congressional in 2011.

"If he does it for two more days, then we're all playing for second spot," said Adam Scott, the world's No. 1 player.

Scott shot 67 in the second round to get back to even-par 140, and that score is the third-best round in the tournament -- behind the two posted by Kaymer.

Nobody has been able to do on one day what Kaymer has done for two at Pinehurst, where he has hit 25 of 28 fairways and 26 of 36 greens in regulation. His closest pursuer is Western Pennsylvania native and Byron Nelson Classic winner Brendon Todd, and he's at 4-under 136 after a second-round 67.

"Watching him hit every fairway, hit every green and make every putt was pretty awesome," said Keegan Bradley, who played with Kaymer and is eight shots back after a second-round 69.

Brandt Snedeker, who has made 10 birdies in two days, is tied with Kevin Na at 137.

"It's not a done deal," Kaymer said. "There's never a time when you can relax unless it's Sunday afternoon and you can raise the trophy."

Kaymer has been so impressive that he is ahead of the two greatest scoring performances in U.S. Open history -- the record 15-stroke victory by Woods at Pebble Beach in 2000 when he became the first player to finish double digits under par; and McIlroy's all-time scoring record of 16 under when he won by eight shots at Congressional in 2011.

Kaymer's six-shot lead after 36 holes ties the record set by Woods and McIlroy in each of those tournaments.

"I played Congressional [in 2011] and I thought, I mean, how can you shoot that low?" Kaymer said. "And that's probably what a lot of other people think about me right now."

Of course, there is always the possibility Kaymer could do what Gil Morgan did in the 1992 U.S. Open at Pebble Beach when Morgan, who had a five-shot lead after 36 holes, became the first player in tournament history to reach 10 under.

Morgan did that early in the third round, expanded his lead to seven shots when he reached 12 under, then finished with three bogeys and three double bogeys to shoot 77. Morgan shot 81 on the final day and finished eight shots behind winner Tom Kite.

"I'm hitting the ball very solid right now," Kaymer said. "It's important to keep going forward and not relax."

As good as he was in the opening round, when he made six birdies, Kaymer was even better the second time around.

Playing in the morning with the course softened by an overnight rain, he hit 12 of 14 fairways, 15 of 18 greens and never made a bogey. When he bunkered his tee shot at the 216-yard sixth and his approach at the 412-yard seventh, Kaymer calmly blasted to tap-in range each time to save par.

"He's just as dialed in as I've seen," said Bradley, who finished with two birdies in the final three holes and is one of five players at 2-under 138. "He's just very steady. He doesn't seem to get too up and down. That's a good combination for a U.S. Open."

Kaymer is trying to win his second major championship after winning the 2010 PGA Championship at Whistling Straits in Kohler, Wis. Like Pinehurst, Whistling Straits is a raw, links-style course with scruffy waste areas and wispy grasses.

"The U.S. Open, you know coming to the golf tournament, it's going to be tight fairways, thick rough, fast greens, and this week it's little bit different," Kaymer said. "I think for us Europeans, or especially the guys from the U.K., we're more used to playing those golf courses than the thick rough or long holes with tight fairways. So I think it's a little bit of a favor for the European players, because we are used to playing those golf courses more."

Gerry Dulac: and Twitter @gerrydulac.

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