So, Phil Mickelson, chasing a major-record round of 62, gets a touch of winner's luck as his tee shot narrowly avoids a bunker on the 18th.

He looks frustrated, but it could have been worse for the American - and with the form he is in today you wouldn't bet against him pulling this one back.

Thomas Mitchell Morris, known as Old Tom Morris, is the oldest winner of the Claret Jug, winning The Open in 1867 aged 46 years and 102 days.

Phil Mickleson is currently 46 years-old and 28 days.

Back on the 15th fairway and Dustin Johnson finds the guts of the green with his second shot. He'll have a 10-footer to get to two under. It looks pretty straight and Dustin gives it a couple of rolls too many, the ball horseshoeing out of the hole.

Martin Kaymer is already lining up his putt, across the green but he can't nail a 30-footer so he stays four under.

Phil Mickelson is in with a shot at matching the record opening round for an Open Championship - that was 63 set by Rory McIlroy at St Andrews in 2010.

The American moves one shot closer to that record with another birdie, this time at the par-three 17th.

He holds a three-shot lead and is on eight under heading into the 18th hole,where he needs another birdie for a round of 62.

There's always one, we're looking at you Pete.

Well, we said Phil Mickelson had made the par-five 16th difficult for himself by finding the sand, but a superb bunker shot gives him a birdie chance and the American does not pass it up.

He moves to seven under, a two-shot lead, and is currently on for his best round ever at an Open Championship.

It's not quite as good as Lee Westwood's shot on the 16th but Bill Hass goes mighty close to an eagle three on the par-five hole.

Lee Westwood, with four bogeys to his name so far, goes and chips in on the 16th to eagle the hole and move back on to level par.

The Englishman has two to play today.

Image source, Getty Images

Well, it's all been going swimmingly for Phil Mickelson so far but the American had to contend with a bunker at the 16th.

Using an iron off the tee on the par-five hole to avoid the ditch, Mickelson's next shot found the sand.

But the five-time major champion has coped with this back nine with relative ease up to this point, and he then goes and puts his bunker shot on the green. Title-winning form.

Dustin Johnson hits his tee short on the par-three 14th 25 feet short of the hole and leaves his birdie putt about 25cm shy to stay at one under. 

Scotland's Russell Knox is dropping back to one over par though, missing a par putt.

Martin Kaymer from eight feet, takes a look at the hole but spins round and away. Tap-in par to stay four under.

Gerald Scott
BBC Sport at Royal Troon

English golfer Robert Rock is renowned for being professional golf's only hatless player.

Rock simply does not like sporting headwear as it makes him feel hot and uncomfortable.

But today the man from Rugeley, Staffordshire wore an old-fashioned flat hat, complimented by an eye-catching shirt, which bore the black and white imprint of a famous old picture of the first Open champion, Willie Park.

Image source, Getty Images

Championship leader Phil Mickelson stays six under with a solid par on the difficult 15th hole.

The past two winners of the Open Championship, Zach Johnson and Rory McIlroy, carded six under par first rounds on the way to their respective titles. 

Can Mickelson, with three holes to play today, follow suit?

A delicate chip shot from Martin Kaymer helps him remain on four under after being well short of the green after two strokes.

Playing partner Dustin Johnson pulls a putt wide and that would have taken him to two under. But it is not to be, and he stays one under.

But there is great news for Scottish fans as Russell Knox is back to level par with a birdie on the 13th. He is now the best performing home player and will be a lot happier now than when he was three over through three.

Two birdies in the final three holes leaves Denmark's Soren Kjeldsen on four under for the day, two shots off the lead.

The 41-year-old was out in 33, back in 34 for a first-round 67 that currently has him in tied third.

A cracking second shot from Russell Knox on the par four 13th, leaves him within 10 foot of the pin.

The Scot started with three dropped shots - a double bogey on the second and a bogey on the third - in his opening three holes.

He has a great opportunity to move level par for the first time since the first hole. Could be good news for the home fans.

You're not wrong Geoff.

Dustin Johnson uses his driver to wallop his tee shot on the 13th. It bounces off the fairway, but no harm at all done - a decent lie. He will be satisfied, but not ecstatic, with that one.

The American finished tied second at the Open in 2011, will this be his weekend as he looks for back-to-back majors after victory at the US Open last month?

Amid the flurry of Americans making their way to the top, England's Andy Sullivan has crept on to three under par through 13 holes.

The 30-year-old, whose best Open finish was tied 30th last year, has carded five birdies so far - only one less than leader Phil Mickelson - but a pair of bogeys on the front nine have cost him slightly.