Shane Lowry is just four shots off the lead but Rory McIlroy barely made the cut before a late mistake by amateur Nick Hardy helped  14 others make the weekend on five over in the car crash US Open.

Chambers Bay's erratic greens, coupled with the firm conditions and shelter skelter slopes have turned the blue riband US Major in the demolition derby with grand slam chasing Jordan Spieth (67) tied for the lead on five under with Patrick Reed (69), who looked certain to lead outright before he bogeyed the last.

The head the field by one from Branden Grace (67) and Dustin Johnson (71), who got to seven under par before bogeys at the 14th 17th and 18th cost him on another day of disasters and drama that saw Graeme McDowell (74 74 for +8) and Darren Clarke (77 80 +17) miss the cut.

While Joost Luiten  (69), Tony Finau (68),  Daniel Summerhays (67) and Ben Martin (70) are tied for fifth on three under, the two unders include Aussie Jason Day, who suffered a bout of Benign Positional Vertigo on his final hole and crumpled to the ground as he left the tee.

After a long wait to get him back on his feet, he clambered unsteadily into a greenside bunker to hit a recovery shot. Wobbling on Bambi legs, he splashed out well and eventually two putted for a bogey and a 70.

It's unclear if he will be able to play in round three but wild horses will not stop Lowry, who grew in confidence with every hole and finished like a major champion with a stunning, 188 yard approach to 18 inches a the 18th setting up a birdie and a level par 70.

The Clara man felt comfortable in the majors for the first time last year, when he finished in the top 10 in the Open at Royal Liverpool.

Having shot 69 in tough Thursday afternoon conditions, Lowry birdied the fifth, bogeyed the sixth but then birdied the par-five eighth to turn for home with the leaders in his sights.

And even though he double bogeyed the 14th, he kept his composure with ease and shrugged off a brace of missed birdie chances that superb birdie at the 18th.

"I went out there today and I thought the setup might be a little bit tougher, Lowry said. "The tees were further back on some holes. I knew if I kept doing what I was doing yesterday, trying to hit some good putts and see what happens.

"And I was going along nicely, missed a great chance on 12, thought if I hit a great putt there to get to 3-under for the tournament, I would have been cruising  then. I felt I got unlucky on 14 and just pulled my second shot. Got an awful lie in the bunker and ended up making double from there. Just one of those -- I hit a great shot into 15, great shot into 16, holed a great par for 17 was massive.

"Probably ten feet, which was kind of -- that was big in regards to the whole round.  Then I went on to birdie the last, which was nice. It was  one of those days that I'm quite happy with. It could 
have been a little bit better, but I'm in a great position for the weekend." 

Pleased with his play from tee to green, Lowry admitted that it's taking him time to get is confidence going on the tricky greens,

"The good thing for me is I'm feeling a bit more comfortable on the greens. Not 100 percent, but I'm liking what I'm doing and liking the way I'm hitting my putts. Relax the rest of the evening, hopefully have a nice late tee time tomorrow, looking forward to it."

Making just his third US Open appearance having missed the cut in 2011 and last year, he was pleased to take another step forward in his career but refused to get too carried away about what might lie ahead.

"You never know. It's a bit early to be  talking about winning. There's lots of golf to be played 
yet, so if I could just keep doing my own thing, I'm driving the ball well. My iron play is good. My putting is getting to where I want it. You never know what can happen on Sunday. 

"To be honest I felt quite in control of  myself all day yesterday and today. It feels good to be here and feeling like the way I felt the last couple of days. I was in control of myself, my emotions and everything. Just need to keep that intact the next few days. 

"My game feels very good."

Rory McIlroy traditionally struggles in hard and fast conditions, especially when the greens are bumpy.

But he showed a lot of maturity in round two and almost dragged himself onto the fringes of contention only to undo all his hard work over the closing holes.

One over for the day and three over for the tournament with seven holes to go, he was teetering on the projected four over cut line when he got lucky at the driveable 12th, got a fortunate kick onto the green from the right rough and took advantage by holing a 12 footer for an eagle two.

Suddenly just one over, he almost doubled the next when he missed the 100-yard wide fairway in the deep rough and had to hack out. 

But he then missed the green with his third and had to holed a six footer just to save bogey. A birdie two at the next got him back to one over but he went long on the par-three 17th and totally overhit his first putt, rushing it 25 feet past. A four-putt added up to a double bogey five and left him needing no worse that bogey at the last to make the cut.

He drove into sand, however, and was forced to lay up and then nervously two putt for a bogey five. 

As it turned out, he made the cut with a shot to spare are amateur Hardy helped all the players on five over to make the top 60 and ties.

Darren Clarke made no complaints about the test from tee to green but a Vine was all that was needed to explain his feelings about the greens.

Even Ernie Els could not resist having a go at the USGA:

As for the tournament, given the state of play at halway in the previous six majors, a Monday playoff could be on the cards.

USGA CHAMBERS BAY UNIVERSITY PLACE, WASH.
T1 United States Jordan Spieth -5 F* -3 68 67 135
T1 United States Patrick Reed -5 F -1 66 69 135
T3 South Africa Branden Grace -4 F -3 69 67 136
T3 United States Dustin Johnson -4 F +1 65 71 136
T5 Netherlands Joost Luiten -3 F -1 68 69 137
T5 United States Tony Finau -3 F* -2 69 68 137
T5 United States Daniel Summerhays -3 F* -3 70 67 137
T5 United States Ben Martin -3 F E 67 70 137
T9 United States Jamie Lovemark -2 F -2 70 68 138
T9 United States J.B. Holmes -2 F -4 72 66 138
T9 Australia Jason Day -2 F* E 68 70 138
T12 United States Kevin Kisner -1 F -2 71 68 139
T12 Ireland Shane Lowry -1 F E 69 70 139
T12 United States Brian Campbell (a) -1 F +2 67 72 139
T12 France Alexander Levy -1 F -1 70 69 139
T12 Sweden Henrik Stenson -1 F* +4 65 74 139
T17 Argentina Andres Romero E F* -1 71 69 140
T17 Australia Cameron Smith E F E 70 70 140
T17 United States Matt Kuchar E F +3 67 73 140
T17 United States Jason Dufner E F* +2 68 72 140
T21 Australia Geoff Ogilvy +1 F* +2 69 72 141
T21 England Paul Casey +1 F -1 72 69 141
T21 United States Jack Maguire (a) +1 F -2 73 68 141
T21 Japan Hideki Matsuyama +1 F +1 70 71 141
T21 Australia Adam Scott +1 F +1 70 71 141
T21 Italy Francesco Molinari +1 F* +3 68 73 141
T21 United States Brandt Snedeker +1 F* +2 69 72 141
T28 South Africa Ernie Els +2 F* E 72 70 142
T28 United States Ollie Schniederjans (a) +2 F* +3 69 73 142
T28 England Lee Westwood +2 F -1 73 69 142
T28 England Justin Rose +2 F* E 72 70 142
T28 Australia Marcus Fraser +2 F* +1 71 71 142
T28 United States Kevin Na +2 F +2 70 72 142
T28 Scotland Marc Warren +2 F* +4 68 74 142
T35 United States Beau Hossler (a) +3 F +2 71 72 143
T35 South Africa Charl Schwartzel +3 F E 73 70 143
T35 South Africa Louis Oosthuizen +3 F* -4 77 66 143
T35 England Tommy Fleetwood +3 F -1 74 69 143
T35 United States Mark Silvers +3 F +1 72 71 143
T35 Chinese Taipei (Taiwan) Cheng-Tsung Pan +3 F +2 71 72 143
T35 United States Phil Mickelson +3 F* +4 69 74 143
T35 United States Cameron Tringale +3 F* -2 75 68 143
T35 United States Chris Kirk +3 F +3 70 73 143
T44 Canada Brad Fritsch +4 F +4 70 74 144
T44 United States Brad Elder +4 F -2 76 68 144
T44 United States Denny McCarthy (a) +4 F* +3 71 73 144
T44 England Luke Donald +4 F +1 73 71 144
T44 United States Ryan Palmer +4 F E 74 70 144
T44 United States Charlie Beljan +4 F* +5 69 75 144
T44 United States Billy Horschel +4 F +2 72 72 144
T44 United States Zach Johnson +4 F* +2 72 72 144
T44 United States Sam Saunders +4 F +2 72 72 144
T44 Australia John Senden +4 F +2 72 72 144
T44 United States Robert Streb +4 F* E 74 70 144
T44 United States Kevin Chappell +4 F* +5 69 75 144
T44 N. Ireland Rory McIlroy +4 F +2 72 72 144
T44 United States Jim Furyk +4 F* +3 71 73 144
T44 United States Brooks Koepka +4 F* +2 72 72 144
T44 United States Keegan Bradley +4 F +1 73 71 144
T60 United States D.A. Points +5 F* +1 74 71 145
T60 South Africa George Coetzee +5 F +3 72 73 145
T60 South Africa Thomas Aiken +5 F* +1 74 71 145
T60 United States Jimmy Walker +5 F* +3 72 73 145
T60 England Ian Poulter +5 F* +3 72 73 145
T60 Colombia Camilo Villegas +5 F +3 72 73 145
T60 Scotland Jimmy Gunn +5 F +3 72 73 145
T60 United States Andy Pope +5 F* +1 74 71 145
T60 United States Troy Kelly +5 F +3 72 73 145
T60 England John Parry +5 F +3 72 73 145
T60 Argentina Angel Cabrera +5 F* +5 70 75 145
T60 United States Morgan Hoffmann +5 F +4 71 74 145
T60 Spain Sergio Garcia +5 F +5 70 75 145
T60 Scotland Colin Montgomerie +5 F* +6 69 76 145
T60 United States Webb Simpson +5 F +3 72 73 145
T60 United States Nick Hardy (a) +5 F* +5 70 75 145
MISSED CUT
MC United States Roberto Castro 74 72 146
MC United States Bill Haas 73 73 146
MC United States Charley Hoffman 76 70 146
MC South Africa Garth Mulroy 74 72 146
MC United States Cody Gribble 68 78 146
MC England Andy Sullivan 72 74 146
MC Japan Hiroyuki Fujita 72 74 146
MC Germany Marcel Siem 73 73 146
MC Germany Martin Kaymer 72 74 146
MC United States Tom Hoge 73 74 147
MC United States Hunter Mahan 73 74 147
MC India Anirban Lahiri 75 72 147
MC United States Michael Putnam 70 77 147
MC United States Timothy O'Neal 74 73 147
MC United States Jason Allred 74 73 147
MC France Victor Dubuisson 74 73 147
MC United States Bubba Watson 70 77 147
MC Austria Bernd Wiesberger 72 75 147
MC China Wen-Chong Liang 73 74 147
MC Canada David Hearn 72 75 147
MC Japan Masahiro Kawamura 70 77 147
MC South Africa Retief Goosen 77 71 148
MC Sweden Alex Noren 73 75 148
MC Thailand Thongchai Jaidee 71 77 148
MC United States Matt Mabrey 74 74 148
MC United States Brian Harman 69 79 148
MC United States Lee McCoy (a) 74 74 148
MC N. Ireland Graeme McDowell 74 74 148
MC Spain Miguel Angel Jimenez 69 79 148
MC United States Russell Henley 71 77 148
MC United States Kevin Lucas 74 74 148
MC England Jason Palmer 76 73 149
MC India Shiv Kapur 72 77 149
MC Japan Ryo Ishikawa 74 75 149
MC United States Bryson Dechambeau (a) 74 75 149
MC Scotland Bradley Neil (a) 76 73 149
MC England Danny Willett 72 77 149
MC United States Bo Van Pelt 73 76 149
MC United States Lee Janzen 73 76 149
MC United States Ryan Moore 75 74 149
MC United States George McNeill 75 74 149
MC Korea Byeong-Hun An 73 76 149
MC United States Matthew Nesmith (a) 76 73 149
MC South Africa Tjaart van der Walt 77 73 150
MC Australia Marc Leishman 73 77 150
MC Scotland Stephen Gallacher 78 72 150
MC United States Erik Compton 76 74 150
MC United States Jake Knapp (a) 74 76 150
MC United States Tyler Duncan 78 72 150
MC United States Jared Becher 78 72 150
MC United States Steve Marino 75 75 150
MC Denmark Lucas Bjerregaard 73 77 150
MC United States Kyle Jones (a) 78 72 150
MC Korea Gunn Yang (a) 74 76 150
MC Wales Oliver Farr 73 77 150
MC United States Blayne Barber 78 73 151
MC United States Gary Woodland 74 77 151
MC Wales Jamie Donaldson 74 77 151
MC England Sam Horsfield (a) 75 76 151
MC Japan Shunsuke Sonoda 78 73 151
MC United States Brandon Hagy 74 77 151
MC United States Billy Hurley III 80 72 152
MC New Zealand Danny Lee 78 74 152
MC United States Michael Davan 77 75 152
MC United States Brendon Todd 78 75 153
MC United States Davis Riley (a) 73 80 153
MC Australia Kurt Barnes 72 81 153
MC United States Rickie Fowler 81 73 154
MC United States Josh Persons 79 75 154
MC United States Richard Lee 74 80 154
MC Germany Stephan Jaeger 74 80 154
MC Denmark Sebastian Cappelen 70 85 155
MC United States Pat Wilson 79 76 155
MC United States Rich Berberian Jr. 83 72 155
MC United States Lucas Glover 73 83 156
MC United States Tiger Woods 80 76 156
MC Korea Seuk Hyun Baek 74 82 156
MC N. Ireland Darren Clarke 77 80 157
MC United States Cole Hammer (a) 77 84 161
MC United States Alex Kim 80 86 166
WD United States Matt Every 78 78