Second shot for Dustin Johnson, who found some rough off the tee. He flings it high into the New York sky, it comes down flush on the green and sticks.

Leader Brooks Koepka digs his approach out of the ankle-high grass to the fringes of the green.

How does Justin Rose get out of this one? He clips on to the green, watching his ball fizz towards the flag, and that'll leave a tough, mid-range putt just to make bogey.

Oh no. It rushes on by, never catching the line. Rose is dropping here... he cards a six, and it takes him back to six over.

Matthew Fitzpatrick with yet another birdie opportunity, this time on the 11th. It's straight up the hill, from 15 feet.

How has that missed? His ball is heading for the centre of the cup up until about six inches from the hole when it drifts left. Matt looks on forlornly.

A tap-in par though.

First blip in Brooks Koepka's round, starting his drive left at four and failing to bring it back. That's nestles into some longer grass.

Dustin Johnson hits almost exactly the same shot.

Justin Rose is in the sand off the tee again, but that's a decent lie.

He coaxes it up towards the green, but it drops way short and left and that's burying itself in a gully between bunkers.

Serious work to do, with a tricky foot placement. He fluffs it, just about clearing the bunker and reaching the fringes.

Image source, Getty Images

Daniel Berger fires long from the greenside bunker on the second - his ball dribbling off the back edge and he can't get up and down in two to save par.

Tony Finau is also dropping. He hacks out of the hay to a dozen feet but he cannot hole the putt.

Both drop to +4

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Huge chance for Dustin Johnson after that superb recovery from the rough at three.

Seven feet for birdie. He stings it in, but it's not hitting the target.

Brooks Koepka is playing immaculate golf. He's left with a four-foot putt for birdie. Down it goes... all smiles for the 2017 champion!

Koepka takes a two-shot lead.

Anything you can do...Matthew Fitzpatrick holes a six-footer on the 10th to notch his fourth birdie of the day to join fellow Englishman Tommy Fleetwood on +4.

But they are now three off the lead...

Tommy Fleetwood's birdie-fest is continuing. The Southport man follows up birdie on 12 with another, from three feet, on 13.

He's suddenly at +4 and right back in this and could set a challenging clubhouse target.

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Another couple of pars ticked off for the chasing pair of Henrik Stenson and Justin Rose.

Solid start, but elsewhere the birdies are dropping...

Dustin Johnson finds the rough off the third tee, but recovers superbly as he runs one right up towards the flag. The pitched way out, but skittled on up to the green.

Brooks Koepka goes fairway-green, and then shoots straight at the flag. Menacing.

Masters champion Patrick Reed is human. He can't convert his birdie chance at the par-four fourth from inside nine feet.

Still, he is three-under-par after four holes and just one shot adrift.

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Justin Rose skirts the fairway at three and then slings his approach to within 18 feet.

It's a solid looking birdie putt. It's got the legs, but not quite the direction. Should be a straightforward par.

Henrik Stenson zig-zags across the green with his putter. Eight feet for par.

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After nerve-settling pars on the first, it's on to the long par-three second for our final pairing - just 264 yards today - and Tony Finau is long and left, his ball careering through the green at pace and disappearing into knee-deep rough.

Daniel Berger is short and right, in a greenside bunker.

Masters champion Patrick Reed plants his second shot into the par-four fourth inside nine feet. A fourth successive birdie coming up? Don't bet against it.

Brooks Koepka holes his birdie chance to move into the lead on +2.

But here's Daniel Berger on the first, from five feet to join his fellow American atop the leaderboard....nope. Pulled it.

Matthew Fitzpatrick, the 2013 US Amateur champion, is through his first nine holes in three under after a par on the ninth.

Tommy Fleetwood has a fifth birdie of the day, at the 12th and is also +5.

But Ian Poulter's challenge appears to be over. Successive bogeys on the fourth and fifth holes has dropped him to +9.

Image source, EPA

What a start from the Masters champion. Three birdies to start for Patrick Reed.

This one at the par-four third drops in from four feet.

He has not put a foot wrong in three holes.

Image source, Graeme McDowell Twitter

John McEnerney: Big Henrik Stenson has the last day major win experience and he showed glimpses of his class yesterday. He’ll be there and there abouts today but that putter of his needs to stay hot. Pin placements today should produce some low scoring.

A couple of cracking tee shots from Dustin Johnson and Brooks Koepka at the par-three second.

Both setting themselves up for a stab at an early birdie. Koepka a little closer than DJ.