Here we go! Is Bryson DeChambeau coming alive?

He watched masters champion Hideki Matsuyama miss his birdie putt down the hill and made the appropriate modifications to land his in the hole to a massive roar from the crowd.

That's his second birdie of the day. The defending champion's charge begins now, maybe...

Is that a sign that Rory McIlroy is feeling relaxed today? The world number 11 strikes a confident putt into the heart of the hole.

Dustin Johnson has checked out his three-footer from the in front, behind, both sides. Inside left edge I reckon. Par.

But once again Justin Rose fails to make his par putt. A poor start by the Englishman.

Rory McIlroy has reduced a 519-yard par-four hole to a drive and a nine-iron. It is playing downwind though.

The Northern Irishman is slightly long but on the dancefloor and will have a 20-foot look at birdie.

Dustin Johnson, from the rough, deliberately lands his ball short of the green expecting it to release up the green. It doesn't. Stops pretty much stone dead and leaves a tough putt up and over a ridge in the green. Decent effort but goes four feet past.

Justin Rose hits an express putt six feet by.

Rory touches his ball down the slope and it too races by. About four feet. We'll come back for the par putts.

Five holes for Jon Rahm - no pars, three birdies, two bogeys.

This was some birdie, though - it must have been at least 30 feet.

Both of his playing partners, Patrick Reed and Marc Leishman, though, drop a shot on the par four 14th.

Is Hideki Matsuyama letting Bryson DeChambeau's struggles distract him?

The 2017 runner-up lipped out with his chip on to the seventh green and looked set up for par, but he missed the putt and ends up with a bogey.

Meanwhile, defending champion DeChambeau slapped one out of the bunker and missed his par putt too. It's a third bogey and he's on two over.

Former England rugby union captain Chris Robshaw is playing in San Diego nowadays.

He's showing his support for Sergio Garcia. To be fair, with a shirt as snazzy as that, Chris might get a round himself...

Jon Rahm continues his topsy-turvy round with a second birdie to tidy up after two bogeys. Maybe just par the next one, Jon?

Aussie Marc Leishman also claims a birdie on the par five 13th to get back to level par too. A player often in contention in these big Majors.

Rory McIlroy hits his first fairway of the day, on the par-four sixth hole.

Dustin Johnson is also 0 for 4 so far as he steps on to the tee. A groan from the world number one. That'll be 0 for 5 then.

We don't get to see Justin Rose's drive. US TV directors don't like players who are two over par, unless their name is Phil Mickelson.

Bryson DeChambeau promised to "bomb and gouge" the course this year and he's just bombed one way left...

It bounces over one of the spectator pathways and rebounds off some boards. The defending champion has only hit two of six fairways so far.

On the fifth green Rory McIlroy is studying a lengthy birdie putt. He's not given his effort quite enough juice but that's good enough for par.

Dustin Johnson is also suffering from a lack of pace as he misses from a dozen feet.

But it's another shot gone for Justin Rose who hits his second shot into a greenside bunker and fails to get up and down.

It's a tournament that has been dominated by Americans in recent times but there's plenty of European involvement near the top of the leaderboard.

Sublime, Lee Westwood. A 20, maybe 25-foot putt from right to left and he curls it in beautifully.

On his honeymoon with new wife (and caddie) Helen, remember. Really.

Stewart Cink drops a shot and now this group are all level par.

America's Hayden Buckley is the late starter who as the made the biggest moves so far.

The 25-year-old US Open debutant hit a lovely tee shot to sink a two on the eighth and finds himself two off the lead now.

Richard Bland won his first ever European Tour title at the 478th attempt last month, triumphing at the British Masters at the age of 48.

Now, he's tied for fourth place at the US Open - on only his second appearance at the Major.

A magical approach to the green of the par four seventh hole leaves him with an absolute gimme and he disposes of it with aplomb.

Former champion Jordan Spieth might not be having much fun out there yet, but fellow American Scottie Scheffler is having a better time of it.

The promising 24-year-old started out with a birdie and a bogey and has just made his way back into the red with another birdie on his fourth hole.

Scheffler is playing in his fourth US Open, his second as a professional.

A reminder of the leaders, all of whom are in the clubhouse:

• -4 R Henley
• -3 F Molinari, R Cabrera Bello
• -2 B Koepka, X Schauffele

Justin Rose is first to putt for par after all three of the players in his group lag their birdie putts up close.

A rare bad one from Rosey, pushing his effort past the right edge.

Up steps Dustin Johnson, also from about four feet. He's in. Four straight pars for the world number one.

Rory McIlroy is tapping in from two feet. One birdie three pars.

Rose tidies up. Bogey.

Jon Rahm has followed up his birdie opener with two bogeys.

Stewart Cink - the 2009 Open champion, who beat Tom Watson in THAT unforgettable play-off - is the other member of the group featuring Lee Westwood and Paul Casey.

Cink sinks a lovely 15-foot putt to go under par, while Casey follows from closer in to get back to level par after a bogey on the 12th.

Bryson DeChambeau has calmed things down a bit with a par after back-to-back bogeys, but it was not all smooth sailing for the defending champion on the fifth.

He overshot the green and had to chip on from the rough, but managed to get it down in four.

Japan's Hideki Matsuyama also parred to stay on one under.