Four-time US Open winner Jack Nicklaus has gone on to Instagram to express his views on his favourite Major.

Image source, Jack Nicklaus

The ups and downs of a professional golfer are shown on the eighth. Justin Rose misses a birdie attempt but makes par, Henrik Stenson produces a perfectly-weighted 20-foot putt for a birdie and Phil Mickelson restricts it to just a bogey after earlier finding hazard then bunker.

Stenson's two was only the third birdie of day on this hole and takes him into tied fourth on two under.

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Mickelson hacks his way out of the hazard. A shot that leaves playing partners Justin Rose and Henrik Stenson scattering as the ball shoots low across the green. Mickelson gets himself out of one bit of trouble, only to find another, this time in the form of the sand. 

The eighth is a 258-yard par-three. His third shot leaves him an eight-foot putt to restrict the damage to a bogey.

Sergio Garcia is two off the lead on two under after an opening round of 68.

“It didn’t look great early on, but it was nice to birdie four and then I started to give myself some good birdie chances,” the Spaniard, who was two over after three holes, said on Sky Sports.

“I hit my driver really well today and only missed two fairways.

“Every time you win it gives you a bit of extra confidence, so hopefully I can play like I did at Byron Nelson.”

Image source, Getty Images

Image source, Getty Images

Disaster for Phil Mickelson. His tee shot on the eighth sees him slice it well left and ends up in the thickest of thick rough and in a hazard. A round that promised so much for Lefty is ending badly. He was out in one under, and he is currently three over for his last seven holes.

Meanwhile, Jason Day has dropped another shot, at the 16th, and it is back to five over for him.

It is a strange schedule today at the US Open. Some players are playing their first and second rounds. Others have had time to go to the cinema.

Let's just put that Dustin Johnson round into context. How about this for a stat? There was not a single bogey-free round when the US Open was last staged at Oakmont in 2007.

Johnson has done it in round one this year. Can he do it again later on today?

Image source, Getty Images

Image source, Getty Images

A chance for Henrik Stenson at the seventh. A chance wasted. He made a good approach on the seventh, but his birdie putt is three feet short. The Swede is one under.

Justin Rose does not have any joy on the same hole as he drops a shot after underhitting an attempt to save par. As a result the ball drifts off and it is frustration for the Englishman, who falls to two over.

Here's how it stands at the top:

-4: Andrew Landry (18), 

-3: Lee Westwood (18), Dustin Johnson (18)

-2: Shane Lowry (18), Scott Piercy (18), Sergio Garcia (18)

-1: Scottie Scheffler - a (18), Bubba Watson (18), Kevin Streelman (18), Danny Lee (18), Henrik Stenson (15)

Image source, AP

Dustin Johnson has the best PGA Tour scoring average for first rounds this year, but look at how this changes for the final three rounds of each tournament - Round two: third. Round three: 77th. Round 4: 57th.

Will this be the tournament that he can keep his form for all four rounds? 

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Dustin Johnson and Sergio Garcia have both finished their first rounds. And both will be very happy with their performances so far.

Johnson's 67, a bogey-free round, saw him hit 16 greens in regulation and his score of three under leaves him tied second, with England's Lee Westwood.

Garcia is one shot further back after a two-under-par 68. But there is not much time for Johnson and Garcia to reflect on their work.

After the storms yesterday, they are two of the players who will be starting their second rounds after a 30-minute break. A tough schedule. But no-one ever said the US Open was easy.

American Matt Marshall has just produced one of the shots of the tournament for a birdie on the fourth.

He was in the rough, 20 yards past the hole but he chips in, in spectacular style. It does not even bounce. It just vanishes. He stays calm. I would have dropped the club and been off sprinting celebrating.

That takes him to level par, and helps erase the memory of a double bogey on the 12th earlier in his round.

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A loose tee shot from Phil Mickelson leaves him in trouble at the sixth. It is a damage-limitation exercise for the American and he restricts it to a bogey.

But that is now three dropped shots in six holes for Mickelson, whose 46th birthday was yesterday. He is now two-over-par, after being inside the top 10 an hour and a half ago.

It has been a tough day for world number one Jason Day. But finally he has something to cheer as he swings one in from 20 foot for his first birdie of the day - on the 14th.

He is still on four over, eight strokes off the lead, but a rare positive moment in a bleak round for the Australian.

We said Sergio Garcia could make a birdie at the 17th. And he does. He has had an eventful round, consisting of five birdies and three bogeys. But he is now on two over with one to play.

Adam Scott can join Garcia on two under. Well, he could until his 10 foot putt on the 14th does not have enough gas and drops short.

Image source, AP

Ambitious from Sergio Garcia, who has a good stab at an eagle attempt on the 307-yard par four 17th. But it drifts long, although he could still make a birdie.

Phil Mickelson also has an attempt to pick up a shot on the sixth. But like Garcia's, his shot is wayward.

Not only is there the incentive for Dustin Johnson of a first Major win, a good performance over the next few days will also help his push for a place at Rio 2016.

It has been a great day for American Scott Piercy. His score of 68, leaves him on two under and in tied fourth position.

That round is a career best round at the US Open for the world number 67. A doff of the hat to you sir.

BBC Sport app users will need to click on the above link to watch the video.

Here's how it stands at the top:

-4: Andrew Landry (18), 

-3: Lee Westwood (18), Dustin Johnson (16)

-2: Shane Lowry (18), Scott Piercy (17), Henrik Stenson (13)

-1: Scottie Scheffler - a (18), Bubba Watson (18), Kevin Streelman (18), Danny Lee (18), Adam Scott (12), Angel Cabrera (14), Sergio Garcia (16)