Another terrific tee shot by Rory McIlroy down the 12th leaves him with a straightforward wedge into the green. He executes that beautifully too, the ball releasing up to the right level and leaving him with a 10-footer for birdie.

Up the hill, so he can give it a bit of a dart. He does just that and suddenly he's back within two of the lead, with the par-five 13th up next - a little stat for you - no player has scored better on par-five holes in majors since 2010. He is a cumulative -187, 10 shots better than Jason Day's -177.

Oh, Richard Bland. The fairytale is turning into a bit of a nightmare for the British Masters champion.

He overshoots the green on 14 and his chip from heavy rough does not make the green, landing in slightly lighter rough.

Successive bogeys on the way at best - it could be a double if he's not careful.

No, a lovely chip the second time around almost goes in, leaving a gimme. But still a bogey.

Former champion Jordan Spieth joins DeChambeau on three over with his third bogey of the round.

The 27-year-old was in the bunker off the tee and couldn't recover from there.

Looks like DeChambeau is in a bunker too over on the 13th.

After his Covid-enforced withdrawal from the Memorial, when he led the field, there would be fewer more popular winners than Jon Rahm this weekend.

The Spaniard is firmly in contention, a lovely approach shot to the second green spinning back invitingly for a birdie chance he gobbles up.

"It's not there, I mishit it."

Yes you did Bryson, yes you did.

And the price for defending champion DeChambeau is a steady roll backwards of his second shot away from the green, leaving him 55 yards to the hole on the par-five 13th.

Englishman Richard Bland has dropped a shot on the par five 13th. He's back to two under after a struggle in the rough left him a long par putt.

It doesn't look like that bogey on the 10th has affected Rory McIlroy too much. He hits a lovely tee shot on the short 11th, using the contours of the green to feed the ball down towards the hole.

He'll have eight feet to get that short back.

Dustin Johnson is first up. From about 20 feet. Starts left. Stays left. Par.

McIlroy misses on the low side and looks to the sky. Big chance missed.

Justin Rose's miserable round continues. Into the bunker off the tee and then two putts from 20 feet = bogey number five.

This group of stalwarts are going along nicely, perhaps somewhat under the radar.

Paul Casey drops a shot on the par three third but Lee Westwood rolls in a nice birdie putt from 10-15 feet.

As Father's Day approaches (Sunday - if you need to post a card, do it now) Paul Coupland has majorly stepped up his dad duties.

Coupland has given up his job as part of a refuse collection team for Boston Borough Council in Lincolnshire to caddie for his son Dave at Torrey Pines.

This will be Dave's third major and the 35-year-old's story gets more interesting still as he once sold shares in himself to keep his career going.

"He kept saying to me 'Dad, will you come and caddie for me?' so last Thursday I ended up handing my notice in and I'm going to try my hand at caddying now," Paul told BBC Look North.

Dave was doing OK, at four over after 14 holes and his day has just got a whole lot better with a first birdie on the par-four sixth.

Image source, Getty Images

Wow, wow, wow.

Some wanted to bill this US Open as Koepka v DeChambeau, taking their social media spat onto the greens of Torrey Pines.

But it is not looking that way from the defending champion's performance so far.

DeChambeau makes it back-to-back bogeys on the 11th and 12th as his short game continues to let him down.

If a quick internet search is to be believed, sunset in San Diego is due in two hours. It is looking slightly more twilighty out there.

Play was delayed by 90 minutes because of fog this morning and with some groups only through five holes, certain players may not get to finish their first round today.

Stewart Cink joins Paul Casey on one under with a tidy putt on the second green, this group having started on the 10th hole.

Are there any more aptly named golfers than the veteran American? Anyone called Driver? Or Niblick?

A momentum shifter for Rory McIlroy? The bounce is suddenly not quite so pronounced. The facial expressions not quite so calm. The reason? He's missed that short par putt. Didn't start the ball far enough to the left.

Justin Rose is also dropping. A fourth bogey in his opening 10 holes. Dustin Johnson is in for par.

Well, Russell Henley's status as overnight leader is in jeopardy.

Louis Ooosthuizen almost joins him on four under halfway through his round but an eagle putt is just wide. Easy birdie, though, and the South African is one off the lead with nine holes to play.

American Patrick Cantlay waits to take his approach shot on the the 18th - his ninth - as a duck waddles across the green.

Sung Jae Im tries to help it along his way, but the duck will go at its own pace thank you very much.

When Cantlay finally gets to hit the ball, it's an alright effort and lands just beyond the hole. Should be a go at a birdie.

Feel free to send in your duck puns, it's 2am and I'm all out.

Rory McIlroy only has 117 yards to the 10th hole. "Go, go, go," he urges his ball after smashing it out of the fairway bunker. It's a bit like listening to the start of a well-known speedy rollercoaster at a well-known theme park in the midlands.

His ball is not in the mood to listen though. It lands well short of the green and spins back a bit further for maximum disobedience.

A chip up leaves a three-footer for par.

Dreamland for Bland.

There's now a four-way tie for second place - and an all-European one at that as Belgium's Thomas Detry joins the party with a quite beautiful approach to the 8th leaving him a routine putt.

Wow. Absolute beauty of a birdie putt from Hideki Matsuyama on the 11th.

The Masters champion appears to be finding his groove now, sinking a 50 footer that curved round from the front of the green.

Defending champion Bryson DeChambeau is on the other end of the golfing spectrum currently. After landing in another bunker off the tee, a two-putt brings up another bogey.

Dustin Johnson has hit a fairway! The world number one only hit one out of seven on the front nine. But he's just pinged his drive down the middle of the 10th.

Rory McIlroy is in the sand down the right.