After suffering at the hands of the insane slope on eight, Rory chips back on to the green to give himself a birdie chance from 10 feet, which he comes agonisingly close to sinking. Just an inch in it as the ball doesn't quite swing enough.

Take a bow Dustin Johnson. He takes a big risk with a weighty chip from the very edge of a bunker on the ninth - his last - to send it up the slope of the green and back down, flirting with disaster before settling to give him a possible putt.

Adam Scott has an even tougher chip out from the front lip of a bunker on the same hole and comes close to success but falls just in to another bunker right in front of the hole.

Dustin Johnson on his last hole. He finds one of the bunkers to the left of the green. That will make for a very tough shot, chipping out to a downhill slope.

Adam Scott follows the leader straight into the sand.

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Dustin Johnson salvages a par five at his penultimate hole. It keeps him six under, but it could have been so much better for the leader.

The course is cruel to Rory McIlroy, who fires his second to the eighth straight at the flag and on to the green but suffers the same fate as Johnson just a few minutes earlier as his ball rolls away to the right and off the green down the slope. Just one more yard to the left and he would have been OK. Damn you Chambers Bay, damn you!

Dustin Johnson hasn't made many mistakes this round but he has just dropped a bit of a clanger at the eighth, his 17th, opting to chip with his third shot from just short of the green. He lands it on the slope and watches in horror as it flies off down the slope.

Birdie for Marc Warren at 15 courtesy of a solid 15 foot putt. The Scot is back to one under.

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Never mind brown, some of these greens are grey. Stenson lines up another birdie at the 17th and send a long putt on its way. It looks as though it is going to drop but ends up just an inch to the left. Agonisingly close for the Swede, who is joint second on four under.

As you can see from this list of past US Open winners since 2005, champions in the event come in all shapes, sizes and nationalities. Although the last five years have had a European feel...

2014 Martin Kaymer (Ger) 2013 Justin Rose (Eng) 2012 Webb Simpson (US) 2011 Rory McIlroy (NI) 2010 Graeme McDowell (NI) 2009 Lucas Glover (US) 2008 Tiger Woods (US) 2007 Angel Cabrera (Arg) 2006 Geoff Ogilvy (Aus) 2005 Michael Campbell (NZ)

Rory McIlroy's putting continues to let him down. He three putts at seven, having been on the green in two, to drop a shot and move to one over.

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We've not seen much from 2010 champion Graeme McDowell so far but he is nearing the end of his round, which has included two birdies, three bogeys and a double bogey to leave him three over.

Stenson's sole possession of second doesn't last long, though, as Patrick Reed sinks a 12 footer at the sixth to claim a birdie and join the Swede on four under.

Dustin Johnson shows no mercy to the ball on the par-five eighth. He absolutely belts it and finds the fairway. He can be on in two from there.

Henrik Stenson is on a roll. A three at the 16th makes it three birdies on the bounce and he is up to second on four under.

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Dustin Johnson is having an extraordinary day. His big-hitting ways were predicted by many to be a bonus on this course and so it is proving. His short-game hasn't been the worst, either. Another birdie at the seventh - his sixth of the day - has sent him six under for a three-shot lead.

Mickelson has about 10 feet to deal with, but no putt is easy on this and he misses by an inch or two. He then sinks his final putt of the round to pick up a par and finish with a one-under-par round of 69.

Bubba claims a 70 in his opening round.

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Right then, what is Bubba going to pull out the bag here? It is an impossible putt, which is miles away and has a huge sloping green with added lumps in it to contest with. He swings it high but way past the hole. "Way off!" shouts one fan incredulously from the stand, not quite understanding just how tough that was.

His next effort, to try and finish with a birdie, is better but still leaves him with a few feet to take care of.

It is not quite going for McIlroy at the moment. He is searching for a big putt to kick-start things again but it doesn't come at five where he strokes an eight-foot effort just past. But that's an eighth successive par for the world number one who stays level par.

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Bubba is not a happy man at the 18th. Not sure why. He has a minefield of bunkers in front of him and finds his way through them to the green. It'll be a beast of a putt on that up and down green but it could have been a lot worse.

Mickelson makes it look easy with an iron shot that lands the ball within about 10 feet of the hole. He's on to finish with a birdie.

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Super putt from Matt Kuchar, who has a monster to contest with at seven and gets it close. He should make par from there. Up goes the rallying cry from the Kuuuuuch backers.

Cody Gribble finishes with a 68. Great name. Good round.

There is a very good chance that the golfers who have played this morning at Chambers Bay will have the best of the conditions. The ground already has a brownish as opposed to green tinge and it is drying out rapidly. That could make for some interesting play this afternoon.

Mickelson is back in the sand on the 18th from his tee shot. Dustin Johnson is an inch short with his putt on six, preventing him from going six under.

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Defending US Open champion Martin Kaymer was very philosophical when asked about his struggles in the Masters, where his highest finish is joint 31st.

The German had a rollercoaster first four holes at Chambers Bay, starting with a par, followed by bogey, eagle, and double bogey. He is currently level par through 13.

Scott Kelly: Want Tiger to do well this wkend and return to his best. Saddens me so much to see him at 195 in the world, go get em' Tiger!

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That train with the red containers has pulled up alongside the 17th, providing an ugly back-drop for Mickelson, who sends a putt uphill and then down the slope to skip just past the hole to the right. Good effort but he'll have to settle for a par.

Big Phil is now behind Henrik Stenson on the leaderboard. The Swede has just sunk a short putt on the 14th to go two under.