Rory McIlroy is closing in on a maiden major title after extending his lead to eight shots over YE Yang going into the final round at Congressional.
McIlroy, 22, shot 68 to post the US Open's best ever 54-hole total of 199 and become the first man to reach 14 under in its 111-year history.
Yang (70) remained second at six under as Lee Westwood and Jason Day hit 65s for five under with Robert Garrigus.
World number one Luke Donald (74) and Phil Mickelson (77) ended seven over.
Sergio Garcia (69), American Matt Kuchar (69) and Sweden's Fredrik Jacobson (66) all climbed into a contention of sorts at four under.
The record comeback for a last round at the US Open is seven holes, achieved by Arnold Palmer at Cherry Hills in 1960, but the way McIlroy is playing there seems little chance of a repeat of the Masters when he blew a four-shot lead going into the last day.
The Northern Irishman may not have been as accurate off the tee as the first two days but he resumed his exhibition of power and control, following each devastating iron shot with the now-familiar twirl of the club, to continue his imperious march to victory.
McIlroy's masterclass was reminiscent of his boyhood idol Tiger Woods's domination of the 2000 US Open when he won by a record 15 shots at Pebble Beach. Woods's record 54-hole lead of 10 shots from that year still stands, while Henry Cotton was also 10 in front with one round left in the 1934 Open.
Should McIlroy go on to win, he would become the youngest US Open champion since Bobby Jones in 1923 and it would mark the first time a nation other than the United States has won back-to-back US Opens following Graeme McDowell's victory 12 months ago.
McIlroy, who was third at the Open last year and third in the last two USPGA Championships, has now held the lead in six of his last seven rounds in majors.
"I know now how to approach tomorrow. At Augusta it was all a bit new to me," said McIlroy, who led this year's Masters for three rounds before collapsing on the final nine and carding an 80.
"I didn't know whether to be defensive or aggressive. I have a clear mind now and just need to stick to my game plan.
"It would mean a lot to me. Even though it's been a short career I feel I've had enough experiences and feel the time is right to go ahead and win my first major."
On a soft Congressional course betraying the US Open's usual treacherous set-up, McIlroy reached the turn in two-under 34 after birdies on the fifth and ninth and good par saves after hacking out of rough on the third and via the sand on the short fifth.
The tap-in birdie on the long ninth, after narrowly missing with his eagle attempt, took him back to 13 under, the former US Open scoring record he set on Friday before double-bogeying the last.
McIlroy made his first bogey of the week at the short 10th after tangling with a bunker and he rolled in a 14ft putt for a birdie on 11 after catching more rough off the tee. He picked up another shot with another sumptuous approach on 14 but could only make par on the long 16th after finding more sand.
On the 17th he held his nerve to avoid his first three-putt of the week after racing a monster birdie putt 10ft past. And he put Friday's second-round dunking behind him with a safe par on 18 to beat Jim Furyk's 2003 record US Open 54-hole total of 200.
Playing partner Yang, who overhauled Woods to win the 2009 USPGA, showed impressive determination to hang onto second, albeit a further two shots adrift, as he followed 11 straight pars with two birdies in three holes from the 14th.
World number two Westwood, who was 84th on Thursday night after an opening 75, surged through the field with a devastating finish of three birdies in a row from the 13th followed by an eagle on the long 16th.
"My mission was to get myself somewhere into the tournament," said the 38-year-old Englishman, who is also chasing his first major title after two seconds and three thirds.
"Rory's had a big lead in a major and didn't deal with it well before. There's pressure on him with regards to that, so we'll see.
"They don't give trophies away on Fridays and Saturdays. All I can do is control my game and try and shoot as low a score as possible for me."
Australia's Day, 23, who finished tied second at the Masters in April, had six birdies in a bogey-free round, while unheralded American Garrigus edged quietly into the frame with four birdies and a bogey.
McDowell's 69 put him joint 21st on level par, while England's Robert Rock - who only arrived at 3.30am on Thursday following visa problems - carded 76 for four over.