Tiger Woods shares the lead at the halfway mark of the US Open but defending champion Rory McIlroy was among the high-profile casualties.
Woods recovered from an early slump to post an even-par 70 in his second round at the Olympic Club in San Francisco to head into the weekend at one-under overall.
He is joined on that mark by fellow Americans Jim Furyk (69), who won this event nine years ago, and former US PGA champion David Toms (70), two shots clear of their nearest rivals.
Overnight leader Michael Thompson is one of four players at one-over after seeing his three-shot lead evaporate on the front nine on Friday.
Thompson struggled to a five-over 75 - nine shots worse than his opening 66 - to sit alongside 2010 US Open champion Graeme McDowell (72), American John Peterson (70) and Belgian Nicolas Colsaerts (69).
One of the biggest surprises of the day was the performance of 17-year-old high school student Beau Hossler, who led the field at one stage after going 11 holes without a bogey before settling for a 73 and a share of ninth place at three-over.
While the youngster will see weekend action, McIlroy and world No.1 Luke Donald will not.
The 23-year-old Northern Irishman - who won by eight shots last year - fired a three-over 73 to add to his opening 77 to finish at 10-over, two shots shy of the cut.
Donald carded a second-round 72 as he crashed out at 11-over and still without a major title.
Among the other big names to miss the cut were 2010 British Open champion Louis Oosthuizen, US Masters winner Bubba Watson and Dustin Johnson, who won last week's St Jude Classic.
Alistair Presnell is the best of the Australians on four-over in equal 18th position after hitting a four-over second-round 74 while compatriot John Senden is a stroke further back on five-over.
Jason Day (six-over) and Adam Scott (six-over) find themselves in a share of 42nd spot and Rod Pampling is on seven-over.
Aussies who missed the cut were Geoff Ogilvy (10-over), Brendan Jones (11-over), Anthony Summers (11-over) and Aaron Baddeley (14-over).
Woods, meanwhile, posted three consecutive bogeys from the fifth to the seventh holes but recovered with two birdies on the back nine to put himself in prime position for a 15th major title - and first since the 2008 US Open.
"That was not easy," he said. "It got dried out and the wind was swirling a little bit. It was really, really tough and I just had to stay as patient as possible.
"I think I'm in a good spot. This tournament, you just keep plodding along."
Furyk's round included three birdies and two bogeys, while Toms fought back from two bogeys on the front nine with birdies on the 11th and 13th to grab a share of the lead.
McDowell's round could have been so much better after three bogeys on his last four holes saw him fall to one-over.
Still, the Northern Irishman, who won the title two years ago at Pebble Beach, was happy to be in a good position.
"It's just tough to have fun out there, I've got to be honest with you. It's just a brutal test of golf," he said.
"I'm disappointed to bogey three of the last four, but that's what this golf course can do to you in a heartbeat - and if you had offered me one-over-par starting on the first tee yesterday I would have probably snapped your arm off for it."
Among those sharing ninth four shots behind the leaders are Americans Hunter Mahan (71) and Matt Kuchar (73) and South African Charl Schwartzel (70).
Englishmen Lee Westwood (72) and Ian Poulter (75) are at five-over.
Phil Mickelson, who was grouped with Woods and Watson in the opening two rounds, made a birdie putt on the last to sign for a 71.
He is at seven-over and just inside the cut line. Watson, though, missed out after his 71 consigned him to nine-over overall.
Fourteen-year-old amateur Andy Zhang, the youngest player to make the US Open since 1945, also missed the cut after his second-round 77 saw him finish 16-over-par for the tournament.