Erin - World number one Dustin Johnson led an unprecedented exodus of big guns at the 117th US Open on Friday as four players grabbed a share of the lead at the halfway stage.
American favourite Johnson crashed out after he could only card a one-over-par 73, which left him four over for the tournament at the sprawling Erin Hills course in rural Wisconsin.
Johnson's exit came after world number two Rory McIlroy and world number three Jason Day also missed the cut after disappointing rounds.
It was the first time since the rankings system was launched in April 1989 that the world's top three players have all failed to make the third round of a major.
Johnson, who had bullishly expected to do well on a course he believed to be perfectly suited to his game, admitted he was surprised to be out after only 36 holes.
"I felt this is a golf course sets up really well for me, especially if I'm driving it like I did today," Johnson said.
"If you look at the golf course and you even talk to me, Jason or Rory, this course sets up perfect for us."
With Johnson, McIlroy and Day all missing from the weekend action, all eyes will be on a clustered leaderboard which is dominated by players who have never won a major.
England's Paul Casey and compatriot Tommy Fleetwood were bunched on seven under alongside Americans Brooks Koepka and Brian Harman at the top.
Behind the leading quartet, a logjam grouped eight players within two shots of the lead.
Jamie Lovemark, Rickie Fowler and J.B. Holmes featured in a three-way tie at six under.
South Korea's Kim Si-Woo and Japan's Hideki Matsuyama were among five players on five under, which also included amateur Cameron Champ.
Matsuyama, who had struggled in the opening round with a two-over-par 74, produced an electrifying second round seven-under-par 65 to thrust himself firmly into contention.
"I'm very excited and very happy with the score," the Japanese star said. "There were a couple of loose swings out there, but when you shoot 65, you can take those."
American Chez Reavie also scored 65 on a day when Erin Hills failed for the most part to bare its fangs.
With the past six majors going to players who have never won a major before, there is a good chance that run could be extended this weekend.
Casey took his place amongst the leading group after recovering from an early implosion that sent him plunging down the leaderboard.
Casey, who had shot a six-under-par 66 on Thursday, came unstuck with a disastrous triple-bogey eight on the 14th after teeing off on the 10th hole.
However the 39-year-old world number 14 unfurled a sequence of five straight birdies to haul himself back up the leaderboard, carding a one-under-par 71 to finish the day at seven under.
"Not every day you enjoy a round of golf with an eight on the card, but I'm a pretty happy man," Casey said. "It was a bit of a roller coaster."
But while Casey was relieved after his gutsy fightback, it was back to the drawing board for McIlroy and Day after their disappointing exits.
Day, needing a miracle to get back into contention after his opening 79 carded a three-over-par 75, leaving him 10 over.
"I was in the hay too much over the last couple of days," Day said.
"It's been the best preparation going into a major, I felt like, in my career, which is playing in majors and knowing what I needed to do to prep for a tournament such as this," Day said. "It's pretty frustrating."
McIlroy meanwhile - who earlier in the week had advised players unable to hit the fairways to "pack their bags" - was left at five over par after a second-round 71.
Despite a flurry of late birdies it was not enough to turnaround an erratic round littered with errors and missed opportunities.
McIlroy however, who is returning from a hip and back injury, put a brave face on his second consecutive missed cut at a US Open following his exit at the halfway stage in 2016.
"I'm optimistic with where my game is," he said. "Hopefully I've got a lot of the bad stuff out of my system yesterday and some parts today. It's just a matter of getting competitive rounds under my belt.
"I've got a busy summer, so I'm excited to play a lot of golf. I feel like that's going to help me to get back into contention and hopefully try to win some of these things."
Scores on Friday after second round of the 117th US Open at Erin Hills Golf Course, Wisconsin. (Par 72; USA unless stated, a-denotes amateur)
137 - Paul Casey (ENG) 66-71, Brian Harman 67-70, Brooks Koepka 67-70, Tommy Fleetwood (ENG) 67-70
138 - Jamie Lovemark 69-69, Rickie Fowler 65-73, J.B. Holmes 69-69
139 - Kim Si-Woo (KOR) 69-70, Xander Schauffele 66-73, Cameron Champ-a 70-69, Brandt Snedeker 70-69, Hideki Matsuyama (JPN) 74-65
140 - Brendan Steele 71-69, Marc Leishman (AUS) 68-72, Harris English 71-69, Bill Haas 72-68, Charley Hoffman 70-70, Chez Reavie 70-65
141 - William McGirt 70-71, Russell Henley 71-70, Sergio Garcia (ESP) 70-71, Bernd Wiesberger (AUT) 69-72
142 - Satoshi Kodaira (JPN) 73-69, Andrew Johnston (ENG) 69-73, Adam Hadwin (CAN) 68-74, Justin Thomas 73-69, Jonathan Randolph 71-71, Yusaku Miyazato (JPN) 72-70, Thomas Aiken (RSA) 71-71, David Lingmerth (SWE) 73-69, Ernie Els (RSA) 70-72
143 - Jack Maguire 70-73, Eddie Pepperell 72-71, Scottie Scheffler-a 69-74, Matt Fitzpatrick (ENG) 70-73, Trey Mullinax 71-72, Kim Meen-Whee (KOR) 73-70, Kevin Dougherty 71-72, Michael Putnam 73-70, Martin Laird (SCO) 72-71, Patrick Reed 68-75
144 - Brandon Stone (RSA) 70-74, Kevin Na 68-76, Louis Oosthuizen (RSA) 74-70, Jim Furyk 70-74, Kevin Chappell 74-70, Stewart Cink 74-70, Li Haotong (CHN) 74-70, Lee Westwood 69-75, Branden Grace (RSA) 72-72, Jordan Spieth 73-71
145 - Daniel Summerhays 73-72, Keegan Bradley 72-73, Shane Lowry (IRL) 71-74, Steve Stricker 73-72, Ryan Brehm 71-74, Jordan Niebrugge 73-72, Talor Gooch 74-71, Rafa Cabrera Bello (ESP) 72-73, Gary Woodland 72-73, Jason Kokrak 75-70, Zach Johnson 71-74, Matt Kuchar 74-71
146 - Kyle Thompson 76-70, Yuta Ikeda (JPN) 72-74, Pat Perez 76-70, Richie Ramsay 73-73, Peter Uihlein 74-72, Justin Rose (ENG) 72-74, Mason Andersen-a 73-73, Davis Love IV 71-75, Ross Fisher (ENG) 75-71, Lucas Glover 74-72
147 - Chris Wood (ENG) 73-74, Adam Scott (AUS) 72-75, C.T. Pan (TPE) 73-74, Henrik Stenson (SWE) 74-73, Charl Schwartzel (RSA) 71-76, An Byeong-Hun (KOR) 71-76, Maverick McNealy-a 73-74, Alex Smalley-a 73-74, Ryan Palmer 78-69, Bradley Dredge (WAL)74-73, Thomas Pieters (BEL) 76-71, Francesco Molinari (ITA) 74-73
148 - Troy Merritt 74-74, Bubba Watson 75-73, Roberto Diaz (MEX) 72-76, Hideto Tanihara (JPN) 72-76, Paul Dunne (IRL) 75-73, Bud Cauley 73-75, Tyrrell Hatton (ENG)_76-72, Scott Gregory-a (ENG) 75-73, Dustin Johnson 75-73
149 - Gregory Bourdy (FRA) 77-72, Sean O'Hair 76-73, Rory McIlroy (NIR) 78-71, Sam Ryder 76-73, Shugo Imahira (JPN) 76-73, Wang Jeung-Hun (KOR) 76-73, Jon Rahm (ESP) 76-73, Graeme McDowell (NIR) 76-73, Angel Cabrera (ARG) 71-78, Russell Knox (SCO) 73-76, Joaquin Niemann-a (CHI) 74-75, Joel Stalter (FRA) 77-72
150 - Wade Ormsby (AUS) 75-75, Chan Kim 74-76, Brad Dalke-a 78-72, Bryson DeChambeau 74-76, Scott Piercy 72-78, Jimmy Walker 77-73, Ted Potter Jr, 74-76, Andres Romero (ARG) 74-76, Brice Garnett 75-75, J.T. Poston 78-72, Alex Noren (SWE) 73-77, Christopher Crawford-a 75-75
151 - Oliver Bekker (RSA) 75-76, Ben Kohles 77-74, George Coetzee (RSA) 72-79, Matt Wallace (ENG) 76-75, Jason Dufner 76-75
152 - Corey Conners (CAN) 76-76, Alexander Levy (FRA) 77-75, Jhonattan Vegas (VEN) 77-75, Roberto Castro 76-76, Emiliano Grillo (ARG) 76-76, Andy Pope 77-75, Stewart Hagestad-a 77-75, Sahith Theegala-a 77-75
153 - Daniel Berger 78-75, Derek Barron 70-83, Aaron Rai (ENG) 73-80, Gene Sauers 77-76, Nick Flanagan (AUS) 75-79, Jason Day (AUS) 79-75, John Oda-a 78-76, Scott Harvey-a 78-76
156 - Brian Stuard 81-75
157 - Roman Robledo 78-79, Daniel Chopra (SWE) 77-80, Billy Horschel 79-78, Wesley Bryan 76-83, Walker Lee-a 81-83
Withdrew: Danny Willett (ENG) (81)