Bryson DeChambeau goes for a high cut over one of the rare trees still left at Aronimink but the ball drops just short of the 18th green and plugs in the bunker.

It's a tough escape which he plays nicely but he faces a tough putt to save par coming up...

Step forward Ryan Fox. The New Zealander has just become the first player to birdie the 245-yard par-three eighth. A super tee shot in to about eight feet set up the chance and Fox rolled his ball right into the middle of the cup.

With his power, Rory McIlroy is usually licking his lips when he arrives at a par-five, but he misses the fairway at 16. Despite a good lie, he dumps his second in the bunker and aggressively knocks it out of the sand to 14 feet and can't get the putt to drop.

Jon Rahm fluffs one into the same bunker while trying to flop his third over it, but he does well to salvage par.

And having visited the same trap, Jordan Spieth gets up and down for his first birdie of the day, drawing a big cheer from the crowd!

From that woeful tee shot on 17 the chip shot isn't much better from Bryson DeChambeau as he fails to find the green with his ball just holding up in the fringe.

That's another bad bogey to drop to three over and not much in the DeChambeau game is working well right now.

Still early days of course, but you wonder if all the LIV Golf funding saga is just playing on his mind - as DeChambeau is heavily involved in discussions over securing new funding for the team-based league and that can be a drain on his time.

Aldrich Potgieter was the first rabbit out of the hutch on the back nine today and the South African is going along nicely, having just rolled in his fifth birdie of the day on the par-four sixth, his 15th hole.

Sadly for the South African he's also had three bogeys. But with the par-five ninth to end with, he's got a decent chance of finishing strongly.

There's the mark of a great player. Xander Schauffele flails his second at the par-five 16th way right and is fortunate to miss the fans standing over there.

But with plenty of green to work with, he plays a lovely chip across the green and rolls in the putt with minimal fuss to move back to three under.

Another well-played hole fails to bring up a birdie for Brooks Koepka, however, as he leaves his putt hanging on the left edge of the cup.

And Tyrrell Hatton can only manage a par after a disastrous three-hole stretch he played in four over. He needs something to go his way.

Urgh! really ugly shot from Bryson DeChambeau on the par-three 17th. It looks like he's tried to hit some sort of controlled iron shot but it's a weak, low squirt out to the right and into the stands.

DeChambeau's swing has never been what you'd call controlled, and it seems the faster and harder he swings the more comfortable, and more accurate he is off the tee.

Image source, Getty Images

Rickie Fowler dips under par for the first time today thanks to a 33-foot putt as he leads this star group after seven holes.

It'd be great to see Fowler get back to his best form - he's right up there in terms of the old 'best players never to win a major' debate.

Fowler finished top five in all four back in 2014 and has 13 top 10s in his major career without tasting success - yet!

At the gargantuan 529-yard par-four 15th, Rory McIlroy hooks his drive into the rough. He draws a favourable lie and sends his approach straight down the banner, but a firm bounce sends his ball 60 feet past the hole.

The putt is a treacherous left-to-righter, but he judges the pace wonderfully and that's another par.

Jon Rahm and Jordan Spieth are both still hunting their first birdie after matching the Masters champion's par.

A 529-yard par-four is no problem when you can smack a driver 352 yards - but that's NOT Bryson DeChambeau who hit that one, no sir. It was Ludvig Aberg who is not only built like a one iron but uses those long levers to give the ball an almighty smack.

Meanwhile, DeChambeau can chew on as many protein bars and do as many pull-ups as he wants but he only managed a puny 349 yards off the tee....

That's a mighty fine front nine for Stephan Jaeger, who rounds it off with a birdie on the 609-yard par-five ninth to move back to the top of the leaderboard on his own.

He rolled in a 10-footer after executing a superb bunker shot from about 60 yards. Rory McIlroy talked about the front nine being the holes to make your score on this week, and then hang on round the back nine.Over to you Stephan

Ooooh, Brooks Koepka's latest birdie attempt just comes up short. That would have been three birdies in four holes.

He's going well, but I can't say the same for Tyrrell Hatton. After back-to-back bogeys, he's just taken a double after three-putting from 27 feet.

Three over for the tournament and he's sure to be running a bit hot.

A rare penalty for Garrick Higgo has emerged. The South African has been penalised two strokes for being late to the tee for his 07:18 (12:18 BST) tee-time.

Higgo was on the practice putting green but not in the area defined as the starting point at his starting time.

It brought Rule 5.3 into place and could have led to a disqualification but PGA of America said the exemption is if the player is no more than five minutes late and the penalty is applied to their first hole.

Higgo, who had parred the par-four first, has had to write down a six on his scorecard. He birdied the third and ninth holes to wipe out that early blemish, but has just bogeyed the 10th.

"Go!" is the shout from Rory McIlroy as he bashes a long iron towards the green at the long par-three 14th.

He comes up nearly 30 feet short, but a safe two-putt from there yields a third straight par. He's looking a little disillusioned but he's certainly not letting this round get away from him at the moment.

Jordan Spieth and Jon Rahm make it a trio of threes. Five straight pars for Spieth. It's not like him.

Bud Cauley has just rolled in a 50-foot bomb to join the leaders at three under, in what is his fifth US PGA Championship start.

The 36-year-old had his close friend Justin Thomas as the best man at his wedding but has not quite hit the heights of his fellow Alabama college star on the PGA Tour.

Ah, Xander Schauffele's early momentum takes a hit at the 220-yard par-three 14th. After finding the bunker, he splashes out a fairly poor effort by his standards and can't make the putt.

No such worries for Brooks Koepka, though. He uncorks a heat-seeking long iron and rolls in a 12-footer for his two.

But it's more bad news for Tyrrell Hatton fans. Back-to-back bogeys and he slips to one over. A bit ragged after a good start.

A chink in Stephan Jaeger's armour. The German is way right off the tee on the par-three eight. It's playing just the 245 yards today. And while he's almost pin-high, his second shot is out of the rough and he can't get up and down for par. Shot gone and he drops into a share of the lead with 2024 champ Xander Schauffele.

Former Open winner Cam Smith is also at three under. The Australian has just birdied his third hole of the day, the par-five 16th, his seventh hole.

Rory McIlroy takes an iron off the tee for position at the short par-four 13th. No problem there, but he gets his second all wrong, leaving him short and left.

But he possesses a glorious short game and knocks his third to kick-in distance. He seemed to be distracted by some noise behind him during that shot, but it didn't affect the outcome.

Jordan Spieth shows his scrambling skills, too, flopping his third over the bunker and draining a 15-footer to remain level par.

Jon Rahm played a beauty into seven feet, but his birdie putt shaves the left edge of the hole! Big chance gone for the Spaniard.

Image source, Getty Images

At 546 yards, the 15th hole at Aronimink will play as the longest par-four in major championship history.

It's 'only' playing 529 yards today though, so pretty easy...

I wonder what Bryson has got in the bag to tackle that?

Three pars on the long par-three 14th hole as all three play it the safe way, find the middle of the green then take their chances with long-range putts.

None find the cup but it's pars all round. The long par-four 15th is up next...