It's all happening on the 10th, as Brooks Koepka finds the left rough off the tee and can only hack out, find the green and then get down in two from 40 feet for a bogey - his first of the day.

Justin Thomas is no stranger to a dropped shot, he's dropped four already before adding another bogey on 10 to slip to five over and he'll soon start looking over his shoulder towards where a halfway cut might be if this continues.

No birdies today so far for Thomas.

Jordan Spieth found a bunker off the 18th tee and eventually makes bogey to reach the turn in a level-par 35.

Jon Rahm cards a par four and is one over - the Spaniard is yet to a birdie today.

Dustin Johnson almost ends his first nine with a rare birdie, but a solid par means he turns in 40 strokes.

Sam Burns ends his front nine in disappointing fashion with back-to-back bogeys seeing him card a one-under 34 at the turn.

That's a more than decent effort overall but after getting to three under he'll be upset to have given two shots back so quickly.

JJ Spaun almost had some company at the top of the leaderboard in the shape of Im Sung-jae, but the man from South Korea pushes a six-footer for birdie on the 17th wide of the mark.

Scottie Scheffler is asking for an official, a ball is in the fescue in the ditch and he wants to check it is his.

Having confirmed the ownership of the ball the American takes a mighty swing and does well to loop his effort 90 yards down the fairway.

Scottie Scheffler does not like that. He lets go of his driver after sending his ball down the left of the ninth towards the ditch Justin Thomas found himself in.

The reigning US PGA champion is right in the oomska.

Meanwhile, Collin Morikawa is in one of those cavernous bunkers down the right. Both in terrible positions.

Scottie Scheffler runs a seven-wood up the apron of the 287-yard par-three eighth.

It's a decent shot but not quite as good as Viktor Hovland's effort to 13 feet with a three iron. Some strike that.

But it does not translate into a birdie for the Norwegian who is struggling to get anything going.

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Justin Thomas sees his approach spin back off the front of the ninth green so he then needs two putts from there to card a six - which was always a possibility when he took on that risky shot out of the rough.

Maybe it's ego, but there's been a few times today when players could simply take a drop from a bad spot but opt to try to hack it out - but with Oakmont's rough the ball literally could go anywhere.

All three of these men go for the 17th green in one but only Jordan Spieth walks away with a birdie and the 2015 champion is three off the lead held by JJ Spaun.

Jon Rahm makes a par four but it's now three successive bogeys for Dustin Johnson, whose chances of repeating his 2016 win at Oakmont are receding with every hole at the moment.

Really interesting situation on the ninth with the contrast in tactics showing how clear thinking and playing the odds can make a difference.

Justin Thomas and Min Woo Lee both find a ditch off the tee - Thomas opts to hack it out while Lee takes a penalty drop, then knocks his third shot onto the green.

JT's hack shoots across the fairway and into the right rough, from where he can only gouge it out back on to the fairway and then he's hitting his fourth towards the green.

It just shows that the US Open is a mental test every bit as much as a test of golfing ability.

Joaquin Niemann has been one of the form players on the LIV Tour in recent times but he is yet to put it all together in a major.

Six consecutive pars to start for the man from Chile.

Brilliant from Matthieu Pavon, who zips his approach into seven feet on the par-three 14th before dispatching the birdie putt.

The Frenchman was among the chasing pack heading into the fourth round at Quail Hollow last month.

Sam Burns is one of the best putters in the game so why not use the flat stick when off the front of the eighth green?

It's a good effort to get to seven feet but his par putt just trickles wide of the mark and that's a shot gone for the American.

Justin Hastings secured his US Open debut by winning the Latin America Amateur Championship in Argentina in January, and he is the first player from the Cayman Islands to appear at a US Open.

A birdie on the fourth hole takes him to one under par.

Rasmus Neergaard-Petersen is on Luke Donald's radar for the Ryder Cup later this year and no wonder.

The 25-year-old Dane, clips in from the first cut off the right edge of the par-five fourth hole for eagle to put himself in a tie for second.

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Scotland's Robert MacIntyre spoke to BBC Sport's Iain Carter after his level par round of 70:

"I am delighted with that. I thought I played absolutely beautifully. That was as good as I can drive the golf ball. I wasn't trying to hit long drives, just trying to find the fairway. I thought I did that great, apart from on 18.

"That's almost as good as I've got!

"I've never played a golf course as hard. Off the tee, it's the most demanding golf course I've ever played.

"That's up there, it's in the top 10 of the rounds that I've played. Every shot is on a knife edge."

Nearly everyone has missed this left-to-right putt to the right...not Scottie Scheffler, who drains his attempt for a birdie after whipping a wonderful iron shot into 11 feet on the 487-yard par-four seventh.

The American allows himself a little smile. Normal service resumed?

It's nothing if not eventful for Patrick Reed, who followed his incredible albatross with a bogey and now a birdie at the sixth to get back to two under par.

A fine tee shot on the par three landed 10 feet away and he stroked home the putt go back into a tie for fifth place.

Dustin Johnson leaves himself so, so awkward near a greenside bunker on the par-three 16th. He plays a tremendous shot to get back to the green but an up-and-down from the position he was in was almost impossible. Another bogey for DJ.

Jordan Spieth birdies the hole - the second time today that he's bounced back immediately from a bogey by gaining a shot straight back.

A first birdie of the day still eludes Jon Rahm, however, as his putt for a two breaks too much to drop in.

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