Yep, you're right there, Iain. The longest course in major championship history...

All change at the top, as Brian Harman moves into an outright lead at four under after a birdie at the turn.

He can't quite shake off the attention of fellow Americans Rickie Fowler and Charley Hoffman, but there's an Englishman in that chasing pack too.

Tommy Fleetwood has enjoyed a solid start to his US Open campaign and three birdies on the opening nine have put him in contention.

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Deary me, Dustin Johnson.

The world number one criss-crosses the fairway on his way up and flirts with fescue, and it costs him.

He drops two shots after an approach from the long grass comes up short, settling for a seven at the par-five 14th.

Here's a little nugget with which to impress your friends.

Following Phil Mickelson's withdrawal earlier today and with Tiger Woods also absent, this year's US Open is the first major since the 1994 Masters that neither player has featured in the first round.

Mickelson missed the 1994 Masters due to a broken leg suffered in a skiing accident, while Woods was still two years away from turning professional.

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Well, well. Jon Rahm was the name on the lips of many a tipster in the run up to this week's US Open, but it's been a horrible start for the young Spaniard.

He began with successive bogeys, dropped another shot at par-five 14th and has now bogeyed again at the 17th.

And the 22-year-old isn't happy. Facing an 11 foot putt to save par, Rahm rolls it to within a whisker of the cup but sees his effort stay up.

He throws his putter to the floor and gives it a kick on its way down for good measure.

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Brian Harman's got his eye in, that's successive birdies for the American at 15 and 16.

Add that to the one he picked up at 13 and he's three under for the day, giving him a share of the lead.

There's another name muscling in on top spot, too. Brooks Koepka has also just landed back-to-back birdies to go level with Harman and Rickie Fowler.

The drive to the course is back...

Have a watch here.

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The 22-year-old from Wolverhampton is making his major debut having earned his US Open spot by winning the international sectional qualifier at Walton Heath.

The world number 166, who was playing on the Alps Tour six months ago, secured his first Challenge Tour victory earlier this season when he won the Kenya Open.

"It's a dream come true to play in any major, and with it being the US Open it makes it extra special," he said.

"I've just had the best six or seven months of my life."

There will be a few names knocking around this weekend you might not be familiar with, and I'd guess Aaron Rai is one of them.

The English youngster had a dream start to his first major, making birdie at the first.

He's now one over as he hits the turn, having bogeyed at the fifth and seventh.

A steady start to his US Open defence from Dustin Johnson.

The big-hitting American is level through his first three holes. He's out with Martin Kaymer and Jordan Spieth, who are both currently at one under.

Image source, Huw Evans Picture Agency

Ouch. How's that for a start from Billy Horschel? He dropped four shots on the par-five 613-yard first.

What a way to start your championship.

If this was the Grandstand vidiprinter I'd be capping that up - Horschel 9 (NINE)...

And it looks like the fescue has taken its first prisoner.

Westwood will have to go some way to top this effort, though...

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Well, Lee Westwood's round started very promisingly with a birdie on his opening hole - those starting at 10 have enjoyed a few today.

But the Englishman then went and carded a double bogey at the par-four 12th.

Westwood recovered with another birdie at the 13th, a round as up and down and unpredictable as this Erin Hills course so far.

We have an early outright leader... and it's Rickie Fowler.

The American has just gone three under through five, with successive birdies at the 11th and 12th having started his round at the turn.

He leads from a group of four that includes England's Tommy Fleetwood at two under.

Americans Talor Gooch and Brian Harman and South Africa's Thomas Aiken are also tied for second.

Talking of tough courses, here's a handy look at Erin Hills, which is hosting its first major...

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So Dustin Johnson is playing his first major of the year, but how does the world number one see this week panning out?

Fit again after his Masters fall, big-hitting Johnson is bidding to become the first player to win back-to-back US Opens since Curtis Strange in 1988 and 1989.

"I like really tough golf courses," said Johnson, who won by three shots at Oakmont last year.

"I tend to focus more and play better. It's just a very, very difficult tournament to win."

Jordan Spieth is on the money!

The 2015 US Open champion collects his first birdie of the tournament at the par-four 11th, to go one under through two.

No dropped shots in this group yet, with Dustin Johnson carding another par to remain at evens and Martin Kaymer also making par after his opening birdie.

It's already been a hectic week for Dustin Johnson.

The world number one, who missed the first major of the year after slipping on some steps and injuring his back on the eve of the Masters, has just become a father for the second time.

The American wasn't about to miss the US Open, but he did arrive a little later than planned following the birth of son River Jones.

Johnson had said he would not travel to Erin Hills until partner Paulina Gretzky had given birth.

River Jones arrived on Monday and Johnson made it to Wisconsin on Tuesday evening, getting straight out on the course to practice.

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Defending champion Dustin Johnson is up and running as he makes par on his opening hole - which is the Erin Hills 10th - as does Jordan Spieth.

It's 2014 champion Martin Kaymer who has the early advantage in that group of former winners, though.

The German sinks a lovely birdie from around 10 feet to go one under.

Modern technology, hey?