Image source, AP

It's midnight in the BBC Sport library, 7pm local time in Pennsylvania. The shadows are lengthening but there should be around two hours of daylight left. That's plenty of time for Dustin Johnson and co to play the remaining six holes of their second round. Right?

Sergio Garcia's birdie putt wanders wide but he drops the return. DJ has already missed his first putt and has three feet for par. In she pops.

Jason Day escapes with just a bogey five on the 18th, his ninth hole. He is level par for his round, but six over for the tournament.

Here's how it stands at the top:

-4: Andrew Landry 

-3: Dustin Johnson (11*), Lee Westwood

-2: Scott Piercy (13*), Andy Sullivan (12*), Shane Lowry

-1: Sergio Garcia (11*), Jim Furyk (9*), Scottie Scheffler (a), Bubba Watson, Kevin Streelman, Danny Lee, Jason Kokrak (14)

Back down the fairway, Dustin Johnson is out with a wedge from 130 yards. It's straight at the hole. Will it hold? Yes it will. He's got a 15-footer for birdie. There's another ball on the green, slightly closer. That belongs to Sergio Garcia. Birdie shoot-out boys.

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On to the third tee we go and Sergio Garcia smashes a drive up past the Church Pews bunkers. Dustin Johnson loads up and also finds the fairway.

Up on the green and Andy Sullivan has a three-footer for birdie to get to two under for the tournament. And that's a confident putt from Sullivan who has a canary yellow shirt and golf shoes with a matching stripe.

On 18 Jason Day's struggles continue as we finding him hacking out of the cabbage to the left of the fairway. He's still back on five over par and needs to get up and down from 100 yards to avoid dropping another shot.

Scott Piercy had a 10-foot birdie putt a moment ago to move into a tie for the lead on four under. Two missed putts later and he's dropping back to two under. Brutal.

Iain Carter
BBC golf correspondent at Oakmont Country Club

When Garcia is in the mood he's got all the attributes to win this. He just needs to make sure that he doesn't get down on himself. At the moment, he's very much still in the mix.

Sergio Garcia is right in this. The Spaniard, who is not renowned for his putting ability, slots in from three feet for birdie and he's back in red figures at one under par.

The first and second greens are the only two that Dustin Johnson has not hit in regulation - ie in two shots - this week. A quite remarkable stat. The American is out with the putter but he doesn't give that enough of a belt and he's got a nervy right-to-left eight-footer to avoid successive bogeys.

I wonder if he's cursing his decision to 'play safe' off the tee with a mid-iron on the 335-yard par-four.

Great putt Dustin. Great putt. Stays three under.

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Dustin Johnson takes a couple of practice swings outside of the hazard which runs parallel to the second fairway. There's no water or sand, just deep, thick rough. He steps in, not allowing his club to touch the ground, otherwise he will incur a penalty stroke. A wild thrash and the ball pops out but stays short of the green.

Sergio Garcia, who found the fairway off the tee, has a shorter pitch into the green and plays a delightful shot to three feet. A quick chance to get back to one under for the Championship.

Time for me to hand you back to Peter Scrivener, who will be able to tell you all about Dustin Johnson's slight wobble.

A few things to clear up, Sergio Garcia, he of the painful-sounding screams, bogeyed the first. He trudges off to the second and playing partner Dustin Johnson hits a four iron into a hazard down the left of the second fairway.

Is the American going to drop a shot for the second hole in succession after a flawless first 27 holes. 

Jay Townsend
Former American professional golfer on BBC Radio 5 live sports extra

Dustin is probably the longest and straightest driver in golf. But he is a a very poor chipper and he has to sort that out if he wants to win something.

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The run is over. No dropped shots in the opening 27 holes of Dustin Johnson's US Open campaign but now it is a bogey at the first.

The American gave his putt for par everything but missed by inches. The shot was so close that Johnson's reaction was to slouch to his knees. Not only is it his first shot dropped, it is also the end of his share of the US Open lead.

In case you are wondering, Rory McIlroy did not drop a shot in his first 35 holes on his way to winning the 2011 US Open at the Congressional Country Club in Bethesda, Maryland.

An anguished shout of  'hang on' from Sergio Garcia, who sounds like a man in a lot of pain. That's what a misjudged shot can do to you. Again it is to no avail as his third to the first, from the rough, drifts off the back of green, leaving an uphill chip to the pin.

Another player to misjudge one is Jason Day, who ends up in the mud on the driveable par-four 17th. The fans that had been standing around that zone helpfully make a semi-circle to point out where the ball has gone. They are going to be getting a close-up view of the world number one very soon.

Moments later, Adam Scott shows his fellow Australian how to do it, leaving himself with a 20-foot putt for eagle.

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Sullivan makes his bogey putt and is back to one under for the tournament, but it could have been worse for the Englishman.

Will Dustin Johnson drop his first shot of the day? He has to sink one from 20 foot to maintain his bogey-free start to the tournament. He had to lay up short out of the fairway bunker.

Here's Andy Sullivan off the back of the first green and he's not hit that hard enough and this is getting worse with every revolution. The man from Nuneaton was chipping from the first cut but failed to get the ball up the slope in front of him and it wandered off right before gathering pace and nestling back in the rough 30 yards to his right.

He has another go. A bit more straight up the hill this time and he gives it a good bump but he's left with six feet for bogey.

Stewart Gilmour: Good move by Andy Sullivan in first nine of second round.

Dustin Johnson, using the driver on the first tee, finds one of the eight bunkers that line the fairway, before Sergio Garcia plonks his tee shot into the long rough after going left.

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Here's how it stands at the top:

-4: Dustin Johnson (9*), Andrew Landry 

-3: Scott Piercy (10*), Lee Westwood

-2: Andy Sullivan (9*), Shane Lowry

-1: Sergio Garcia (9*), Jim Furyk (7*), Scottie Scheffler (a), Bubba Watson, Kevin Streelman, Danny Lee