Jonathan Jurejko
BBC Sport golf reporter at Royal Birkdale

How do you know it's a dehydrating day at the Open?

When the queue for the water refill is longer than the one at the beer tent...

We talk a lot about staying out of the Birkdale bunkers, but why? Here's Ken again with the lowdown.

Ben Croucher
BBC Sport journalist at Royal Birkdale

You'd think with hard, bouncy fairways carrying the drives beyond 350 yards that the par-fives would be really accessible today but this is Birkdale remember.

Just past 2pm in the opening round and we're still waiting for our first eagle. To put that into context, we had 36 over the course of the four days back in 2017, although only 12 in 2008.

Aggression can be reward but miss but even the slightest margin and the bunkers, humps and hollows are waiting to gobble up stray shots.

Caution may be the better part of valour on a day like today.

Even though leader Alex Smalley failed to cash in at 17, there are a lot of birdies out there today on what has been a pretty amenable first round at Birkdale.

Having said that...

Who needs a driver?! Keeping the headcover on the chief at the par-five 17th - the easiest hole on the course today - Alex Smalley belts a low chaser with a long iron up the fairway and it runs forever, eventually coming to a rest 305 yards up there.

From 248 yards, he hoicks his second into the greenside bunker. It's a horrible distance too - 44 yards - and he chunks it, leaving himself short of the green in three.

From there, he knocks it up to four feet and rolls in the par putt. That'll feel like a bogey, though, especially after a cracking tee shot.

Matthew Hobbs
BBC Sport journalist at Royal Birkdale

Image source, Getty Images

Justin Rose arrived at Birkdale with a combined score of 11 under at the majors this season - a record bettered only by Scottie Scheffler and Sam Burns - but he opted to miss the traditional warm-up at the Scottish Open last week.

The past four Open champions finished in the top 15 at the Scottish Open before their win.

Not the start two-time Open champion Padraig Harrington was hoping for as he makes a bogey on the first - having had a bit of a wait back on the tee which will not have impressed him as a player who likes to get on with things.

Harrington claimed back-to-back Claret Jugs here at Royal Brikdale, with one of the best shots in the competitions' history on the 71st hole with his five-wood through the wind setting him to defend his title.

Oliver Wilson
Former Ryder Cup player on BBC Radio 5 Live

When you see some of the best chippers in the game, their left foot can move. That one looked liked it moved more than normal for Justin Rose.

An unfortunate bogey from a decent tee shot. It looks like he is not quite comfortable. The result of that is his approach play has been poor and there's too much work to do around the greens.

Image source, Getty Images

Justin Rose and Viktor Hovland both find themselves at the bottom of the slope to the right of the 15th green.

Hovland chips to about 12 feet and rolls in the putt to save par.

Rose has a slightly longer par putt but it's just not happening for Justin today. He's at six over and there are only two players below him on the leaderboard at the moment.

American Russell Henley has registered five straight pars since his birdie at the 10th and is even for the day with three holes left for this group to play in round one.

Robert MacIntyre's not the only Scot mixing it at the top of the Open leaderboard, as Jack McDonald gets to three under after 10 holes in what is his second appearance in The Open.

McDonald picked up his fourth birdie of the day at the 10th against just one bogey to move nicely into a tie for fourth place - alongside compatriot MacIntyre.

Joakim Lagergren reached for The Open for the first time courtesy of his top 25 finish on the final Race to Dubai rankings.

And the Swede has made a pretty decent debut today as he walks off the 18th with a two-under 68 in the bag.

Image source, Getty Images

Angel Ayora was out early this morning, sporting attire featuring images of Seve Ballesteros to mark the 50th anniversary of his fellow Spaniard's famous chip on the last at Royal Birkdale in 1976.

That led to a birdie as the 19-year-old finished joint second to announce himself on the world stage.

Seve would, of course, go on to win the Claret Jug three times and be at the forefront of the European rise through the 1980s.

Back to Ayora, who is managed by Seve's oldest son Javier and is making his Open debut... he was one under after nine holes but had a mini-disaster down the last, posting a double-bogey six.

But that is three shots better than his amateur playing partner Mateo Pulcini of Argentina, who was six over after 12 (perhaps he stayed up to watch the World Cup semi-final...) but a birdie down the last might make his lunch taste a little better.

In case you missed it, Robert MacIntyre was out early and lit up Birkdale for much of his opening round.

He's in prime position after day one.

Oliver Wilson
Former Ryder Cup player on BBC Radio 5 Live

Justin Rose is definitely not having a good day.

I spoke to his team early in the week and they were very aware of the situation. The first three holes were really solid and it has fallen apart. He started missing green after green and it has slid away.

He loves the majors. Very few players in the world of golf, real elite players excel at the top of the major leaderboards, and he is one of them. I certainly wouldn't rule him out, but time catches up on everyone.

Tommy Fleetwood just misses a long birdie putt to hit the bounce back on 13, so has to settle for par there but that was a bit more like it from the Englishman.

His round's on a bit of a tightrope right now, he could press to try and pick up a couple of birdes, but that runs the risk of adding a few more bogeys that could put him behind the eight ball already.

An interesting home stretch coming up.

The long par-five 14th is playing more than 600 yards and will be on the fringes of being reached in two by the vast majority of players today.

Viktor Hovland has 10 feet left for birdie to get back under par for his round, but his putt clips the right side of the cup and stays up.

Justin Rose is 20 feet away but his birdie try doesn't drop either.

Pars all round for this group.

Our marquee groups are taking on the new 15th hole at Royal Birkdale shortly, so let's take a look at it with our Ken Brown.

Alex Smalley doesn't give much away while he plots his way around the course, but he's probably a tad disappointed with his approach at the par-four 16th.

It's on the weak side and he's left with a 45-footer, which he lags up and knocks in for par.

No damage there. A four-four finish will give the world number 44 a sparkling opening round of 64.

Jonathan Jurejko
BBC Sport golf reporter at Royal Birkdale

You could say Dan Brown has had a smoking round today. Turns out he literally has.

The 31-year-old Yorkshireman likes a crafty fag on his way round the course and says he got through "seven or eight" in his opening 66.

Brown sounded a bit sheepish in his post-round presser about his habit, but he says it helps settle his nerves and has worked a treat so far.