McIlroy a class apart
Rory McIlroy shot the lowest halfway total in US Open history and will take a record-equalling six-stroke lead over Korean YE Yang into the third round at Congressional.
The 22-year-old Northern Irishman stands 11 under par after adding a 66 to his opening 65.
McIlroy even reached an unprecedented 13 under - and an amazing 10-shot advantage at the time - when he holed from 12 feet at the 17th but, needing a closing par four to become the first player to break 130 for two rounds at any of the majors, he went from rough to water and ran up a double bogey.
Yang then shot 69 to narrow the gap still further from eight to six.
McIlroy remains bang on course, though, to follow compatriot Graeme McDowell as champion - and become the US Open's youngest winner since amateur Bobby Jones in 1923.
Resuming three clear, he made a 25-footer at the fourth and pitched over water to six feet for another birdie on the long sixth.
The unexpected eagle two, courtesy of spinning a 113-yard wedge into the cup, enabled him to turn in 32 and then came further birdies at the 14th from four feet, long 16th - he actually missed a 10-foot eagle chance there - and 17th.
But then came a hook into the rough down the last and a second that curled into the water on the left. He had not had a bogey all week until then.
Spain's Sergio Garcia is part of the group on two under and five-time runner-up Phil Mickelson would have been alongside them if he had birdied the last, but he also found water on the 18th and double-bogeyed for a 69 and one-over total.
Padraig Harrington and defending champion McDowell were both two over after rounds of 73 and 74 respectively, while Lee Westwood had improved from four over overnight to one over with one to play.