Thai qualifier Phachara Khongwatmai, who only turned 17 in May, is the youngest player in the field (11:04 tee-off).

"I'm proud and feel lucky that I have a chance to play in an event like this. It's like an accident that I'm here," said Phachara.

He owes his spot at Troon to his impressive sixth-place finish at the Thailand Golf Championship on the Asian Tour, when he finished ahead of the likes of Martin Kaymer and Bubba Watson. 

"I didn't expect to get a chance to play in a major so soon in my career. If I make the cut here, I'll be happy. If I don't make the cut, I'm also happy," said Phachara, whose first name means 'diamond'. 

Michael Griffiths: McIlroy taken a lot of flak this week for comments but surely its refreshing to hear something truthful from a sportperson for once.

Adam Poots: Bubba will blow up - you heard it here first.

Image source, AP

Four birdies in his first five holes has seen Bubba Watson take a share of the lead on four-under-par alongside fellow Americans Patrick Reed and Justin Thomas.

Image source, Getty Images

Difficult eagle chance for world number one Jason Day on the sixth up the slope, he gets the left to right break but can't find the hole.

Masters champion Willett, coming at the pin from the other side, follows with an eagle opportunity of his own, but has to settle for a birdie.

That's enough to move the Englishman to within one of the lead, however.

We mentioned a minute ago how Sandy Lyle, Scott Gregory and David Duval fell victim to the 11th.

It seems that trio were not the only ones struggling with the par four Railway.

How about this stat from Golfweek's Jim McCabe.

This is the hole that Arnold Palmer, winner in 1962, called “the most dangerous hole I have ever seen” and in the same week Jack Nicklaus, on his Championship debut, ran up a quintuple bogey 10.

That, of course, was when the hole was still a par five.

The first group teed off at 06:35 this morning and have finished their round after four hours six minutes. None of them even broke par...

Colin Montgomerie finished at evens, Luke Donald at +2 and Marc Leishman at +3.

So as Monty wraps up his round, a few other British hopefuls are just getting under way.

Out alongside Japan's Kodai Ichihara and American William McGirt is England's Robert Rock, who tied for seventh at the 2010 Open at St Andrews.

How the 39-year-old would enjoy another weekend like that...

Colin Montgomerie saves par on the 18th to finish on 71 for the first day. 

It was out in 33, back in 38 for Monty - and by my maths that equals par.

Meanwhile, Jordan Spieth has an eagle chance on the sixth, but the American's putt lacks a little pace and he pulls it just short.

It's a birdie for Spieth though, his second of the morning.

Image source, Getty Images

He is a 23 year old American, who turned professional in 2013 and currently has a world ranking of 37.

He won his first PGA Tour title in November, winning the CIMB Classic.  

His first hole in one was at the age of six years old and he used to have putting competitions with Jordan Spieth when he was growing up.

Well, I reckon Hideki Matsuyama's yellow jersey wouldn't be out of place at the Tour de France.

The 24-year-old isn't quite troubling the leaders at Troon yet, but he has started promisingly and sits at two under after birdies on the first and fourth.

Earlier we told you how English amateur Scott Gregory scored a triple bogey on the 11th.

But his playing partners, who happen to be former Open champions, also suffered on the par four Railway hole.

Sandy Lyle carded a seven while David Duval left with a nine.

Ouch.

Image source, Getty Images

Thanks, Luke.

Right, first things first and it's Patrick Reed who has dropped a shot with a bogey on the 10th, taking the American back to four under.

Reed still holds a share of the lead though, with compatriots Justin Thomas and Jimmy Walker also on four under.

Kevin Chappell is another stroke behind. 

Colin Montgomerie may have gotten off to a slow start but he seems to have found his form, including this impressive putt on the 13th for par.  

Right then. It's been a frenetic morning having started this live text four hours ago. I think it's porridge time for me so I will leave you with my colleague Alex Bysouth.

If I could use an emoji in this live text I'd bring the flames one into play for Rickie Fowler as he just took on the par-three fifth admirably, dropping his tee shot to within a few feet.

Jimmy Walker also merits some flames as he moves second with birdie on seven. Just 10 putts in seven holes for Walker.

As you can see, we now have an outright leader as Justin Thomas drops one on 10. Remember, the back nine is where you have to cling on. Thomas pays the price for planting an approach into thick rough. Some would say he got greedy.

-5 Patrick Reed (9)

-4 Justin Thomas (10)

-2 Byeong Hun An (9), Jimmy Walker (6)

-2 12 players including Jim Furyk (10), Padraig Harrington (7), Jamie Donaldson (7), Bubba Watson (3)

-1 15 players including Jordan Spieth (5), Justin Rose (5), Danny Willett (3), Jason Day (3)

Selected others:

E Colin Montgomerie (16), Rory McIlroy (3)

+1 Luke Donald (16)

+2 Shane Lowry (5)

You can see the full leaderboard here., external

Danny Willett is in aggressive mood as we saw with that drive on the first. He converts smartly on the fourth green to make it back-to-back birdies and move to two under.

Jordan Spieth is up quickly and walks after his putt on five as he misses to only make par. Not yet fully settled on the greens.

What about Jason Day, he's also a little ragged. Like Spieth he is one under but a heavy chip on four makes birdie difficult on this par five. In major golf, you have to punish the par fives.

Day only makes par, his birdie effort lacks any conviction.

Michael Schultz: Watched my first Open in 1969, on ABC in the USA. Lefty Bobbie Charles lost to Tony Jacklin in Round 4 by 2. Been hooked ever since!

Neil Foot: Has Rory decided to spend the day improving his sand save percentage?!