BETHESDA, Md. (AP) The double bogey to close the day would have left the average player in a snit.
Rory McIlroy? He's anything but average, and he couldn't help but smile.
Not even the mistakes he made could turn this U.S. Open into a fair fight.
For 17 holes Friday, the 22-year-old from Northern Ireland systematically dissected the monstrous layout at Congressional and put the same kind of hurt on a U.S. Open record book that doesn't change easily.
McIlroy made a 6 to finish the day but by then, the damage was done. He shot 5-under-par 66 to head into the weekend at 11-under 131, setting the record for the best 36-hole score in the 111-year history of the tournament.
"I'm very happy with my position," McIlroy said. "I couldn't have asked for anything more on the first tee this morning."
His 36-hole score was one shot better than Ricky Barnes at Bethpage in 2009 and the gap would've been bigger had McIlroy not hooked his drive on 18 into the trees and knocked the recovery shot into the water left of the green. He made double-bogey there - a bummer of a way to close a round that had been virtually error free until then.
So good, in fact, that after back-to-back birdies on 16 and 17, McIlroy did something nobody had ever done. He reached 13-under par, the lowest score at any point in the history of the tournament, breaking a record held by Tiger Woods and Gil Morgan.
Despite the late hiccup, McIlroy still held an eight-shot lead over Y.E. Yang, who teed off at about the same time McIlroy finished and made pars on his first five holes.
Zach Johnson, Sergio Garcia, Robert Garrigus and Brandt Snedeker finished the day at 2 under. With about half the players still on the course, nobody else was making a run.
"If he keeps playing the way he's playing, we're all playing for second place," Snedeker said.
McIlroy became the fastest player to reach double digits under par at the U.S. Open (26 holes). And he had a good chance of holding the biggest lead at the halfway point of the tournament, a record that belongs to Woods, who led by six after 36 holes of his indelible performance at Pebble Beach in 2000.
Coming off a final-round collapse at the Masters two months ago, McIlroy is still search of his first major. Now, it's just a matter of which way he'll go. Of the four previous players to reach 11-under par or better at the U.S. Open, two have won easily (Woods and Jim Furyk in 2003) and two have melted down (Morgan in 1992 and Barnes in 2009).
McIlroy said he's changed a few things since Augusta.
"I said I needed to be a little more cocky, a little more arrogant on the golf course, and think a little bit more about myself, which I've tried to incorporate a little bit, just on the golf course," he said. "I just try and have a bit of an attitude, you know?"
McIlroy holed out from the eighth fairway for an eagle that got him to 10 under. He made five birdies, 11 pars and still technically doesn't have a bogey, even though he did make the double on 18. He hit 15 more greens in regulation to bring his total to 32 of 36 for the tournament. Before No. 18, even when he got in trouble, he turned out OK. After hitting his approach into the bunker on No. 11, he saved par with a 10-foot putt.
But the signature shot from this day was the eagle on 8. Hitting a short approach, he bounced the ball at the back of the green, it hit twice then spun and rolled slowly before dropping into the cup. McIlroy raised both hands in the air. Phil Mickelson, playing in the same threesome, applauded.
What else could he do?
"He's striking it flawlessly and putted great on the greens," said Mickelson, who shot 69 to close at 1 over. "His first two rounds were very impressive."
McIlroy backed up the eagle with five straight pars, then stiffed his approach on 14 to four feet and made the putt to move to 11 under.
On No. 16, he barely missed an 8-foot eagle putt that would've put him at 13 under. But he got to that number on 17 with birdie following an equally close approach. No player had reached the magical 12-under point at any Open venue other than Pebble Beach, where Woods and Morgan hit the mark.
Congressional is no Pebble, but neither is it turning into the beast it could've been. Soft greens from an overnight rainstorm and forgiving rough took some of the bite out of the 7,500-yard layout. McIlroy's first tee shot went slightly left into that rough but he had no problem wedging it out and onto the front of the green. His shot on 18 was so far left that the thickness of the rough wasn't the issue, but rather the angle he had to come in on.
"I was just trying to play out to the front right portion of the green," he said. "And I just got a little bit of grass caught in between the club face and the ball. The club turned over a bit and that's really all that happened."
Probably no big deal the way things are going.
"He's just playing great," Garcia said, "it's as simple as that."