Andrew Cotter
BBC Sport commentator

The wind is gusting to 34mph.

Brooks Koepka shovels out from the fairway bunker on eleven but he's got work to do to save par now.

There's no adjustment as he lobs a wedge into the wind, leaving him well short of the pin. He'll have a monster putt for a four.

No sign of a collapse from Dustin Johnson after that bogey. He makes a great putt to get within a few feet and taps in for par.

Dustin Johnson had no troubles off the tee after that bogey on the 11th. But the wind has caught his second shot and it goes nowhere. He's just in front of the green on the par-four 12th.

Brooks Koepka looks pretty relaxed as he strides on to the tee at 11.

There's a bit of a waggle before he sets about launching another drive to the back of beyond.

He finds the sand down the left here though, just to keep things interesting, for himself.

Aah this is painful. Matt Wallace pays for a poor tee shot and then a three putt to card an ugly-looking double bogey 6.

To say he looks unhappy is an understatement.

Denmark's Lucas Bjerregaard gets a hole in one on the 17th! He's still +2, but that's the first ace of the championship.

Then, his playing partner Lucas Glover (who, by the way, plays without a glove) chips in after going into a bunker off the tee. Wild scenes!

Image source, Getty Images

Image source, Getty Images

Like the 10th this hole is out in the open and exposed to the winds. The fairway is somewhat blind with deep bunkers guarding both sides and the green is one of the most difficult, sloping steeply from back to front.

Andrew Cotter
BBC Sport commentator

Brooks Koepka has weathered things and is now only one shot worse off than when he started in terms of leading.

Dustin Johnson has got to make a move on the back nine and make up a shot or two in the next couple of holes which won't be easy.

Jordan Spieth hadn't dropped a shot until the 12th and was one under for the day, but he fluffed a shot out of the rough stuff and has his first bogey of the day.

He's still tied fifth.

There it is. Brooks Koepka reinstates his six-shot lead with a straightforward birdie putt on the 10th.

Oh dear. Dustin Johnson's par putt stays right of the hole on the 11th. Brooks Koepka's lead goes back to five, soon to be six?

Meanwhile, there was nothing nervy about Brooks Koepka's shot onto the 10th green. That's landed inches from the hole.

While Dustin Johnson is struggling for par, Koepka will be going for a birdie.

This feels big. Dustin Johson's bunker shot rolls and comes to a stop about 10ft past the hole. Nervy par putt to come.

Harold Varner III is discussing Drake with the NYPD officer on the course. One of my favourite moments of the weekend so far.

Dustin Johnson doesn't look quite as comfortable.

He goes from the rough to a bunker with his second shot on the par-four 11th.

Another huge drive from Brooks Koepka into the middle of the 10th fairway. He's looking very comfortable.

Anthony Wall
Two-time European Tour winner on BBC Radio 5 live

Brooks Koepka is playing stressful golf right now. He always seems to be 30-40 feet away from the hole. But that was a beautiful putt.

How has Brooks Koepka done that?

It looked as though he might struggle for par on the ninth but actually he comes close to a birdie after a mammoth putt. Just a par in the end, the lead stays at four.

That was so, so close.

The ball stops an inch right of the hole and Dustin Johnson leaves the 10th with a par.