Let's check up on the Irish lads, starting with the best of them all - two-time Open champion Padraig Harrington.

Now 50, the Dubliner - fresh off his US Senior Open win - is playing some educated stuff around the links today with three birdies and a bogey. That putting stroke still looks smooth after all these years, too.

Qualifier Ronan Mullarney - who will be a new name to most - is also two-under, playing in the group that teed off last.

And David Carey, who once shot 57 (yes, 57) to win a tournament on the Alps Tour - where he plays most of the time - is level par after eight holes.

Carey played a practice round with Bryson DeChambeau earlier this week. Whether or not it's because they both wear flat caps, I know not, but whatever wisdom the 2020 US Open winner imparted on the Irishman seems to be doing the trick.

Image source, Getty Images

Right on cue, all three of this group do exactly as Alex predicted a few moments ago.

Now it's a chipping contest between Tiger Woods, Matt Fitzpatrick and Max Homa from the wispy rough at the back of the 12th green.

Image source, Getty Images

Seeing as there's been so much talk around the controversial LIV Golf circuit, let's see how the Saudi-funded tour's players are faring.

Pretty well, as it turns out, with 49-year-old Lee Westwood and American Talor Gooch leading the way for the breakaway gang.

Lee Westwood -4 (F)Talor Gooch -4 (F)Ian Poulter -3 (F)Dustin Johnson -3 (15)Bryson DeChambeau -3 (F)Paul Casey -2 (16)

Greg Norman isn't here this week, you may have heard. But wherever he is, he's probably enjoying this.

Alex Bysouth
BBC Sport at St Andrews

With a bit of breeze behind them, the past few groups have been driving through the green at 12 and off into the rough behind… imagine that being your main concern while standing over your ball at the tee?!

Uh oh, sounds like fatigue is setting in for our folks on the Old Course.

Been a long, old day.

Pack the espresso chews and - more importantly - the skinny-fit sweat pants tomorrow, Alex.

Not sure even a UK heatwave knows the east coast of Scotland exists.

Jordan Spieth bogeyed the 10th and falls back to one-under. Considering he had to take an unplayable lie after an errant tee shot found the top of a gorse bush, it's not a disastrous return, but he'll still be smarting.

The scoring is nowhere near as low as it was this morning, that's for sure.

Alex Bysouth
BBC Sport at St Andrews

It’s getting windy out by the River Eden, which is maybe 50 yards from the 12th tee - that breeze brings with it a chill, although perhaps more so for reporters who’ve been out here in shorts since 6am than the players currently slowly working their way around the Old Course.

The momentum has been halted as quickly as it arrived.

After back-to-back birdies, Tiger Woods's momentum is checked by the par-three 11th - known across the sport as 'High (In)' and more colloquially as 'the shortest par five in golf'.

Matt Fitzpatrick also sees his first birdie of the day also wiped out by this devilishly difficult 174-yarder.

World number one Scottie Scheffler is back to four under after recovering from a bogey at the previous hole to birdie the par-five 14th.

A second consecutive birdie moves England's Tyrrell Hatton to one under, and leaves this group - unusually for the afternoon starters - at a collective seven under. Good work.

Iain Carter
BBC golf correspondent on Radio 5 Live

That is the key thing - when it becomes your opportunity to play, you have to feel that you have to crack on and you get out of the rhythm.

Players are dropping shots and they are making errors that you wouldn't usually see from elite players.

You then trudge off the green, and see the group ahead still waiting on the tee.

It is not necessarily players playing slowly - it is just the logistics of St Andrews.

The other highlight from Si-woo Kim's round is an extraordinary print letter jumper. The sort of sweat which you could imagine a 90s hip hop star from Brooklyn wearing while doing a MTV promo on a graffitied subway train.

Tucked away in the mixed zone is BBC Radio 5 Live's Andy Stevenson, who is asking the hard questions when players come off the course.

I think his time with Xander Schauffele may have been relatively easy given the American, who won last week's Scottish Open, shot a three-under 69.

You can listen to the radio commentary by clicking on the link on this page.

Image source, BBC Sport

Another shot goes for Paul Casey and he's back at two under having reached the turn in 32.

The Englishman's now struggling to break 70 when he was probably thinking 66 a couple of hours back.

Moment of the day? Surely.

Si-woo Kim might have been forgiven for thinking his chances of a par on the 17th were over when he landed in the infamous Roadside bunker.

Even more so when he found his ball next to the wall and had to play out sidewards.

Trouble was he didn't play out... it hit the back and rolled back into the sand. Uh oh.

But then, in one of the great mental resets, the Korean not only knocked out close... he holed in!

Cue sheer delight from both player and the crowd. What a save.

Jordan Spieth is forced to take an unplayable lie with his ball having ended up on top of one of the gorse bushes down the left of the 10th fairway.

After the usual player-caddie pre-shot deliberations, he plays a gutsy recovery shot to around 30 feet. Knowing him, he'll probably make that.

Jordan Spieth narrowly avoided the gorse on the ninth, but lady luck has deserted him on the 10th tee as he sends a horrible hook left into the nasty stuff.

It looks like his ball is actually sitting on top of one of the bushes - that's going to be interesting. Is it a good break or a bad one? I don't even know - in 20 years of watching The Open I don't think I've ever seen a ball end up there!

Following Spieth is never dull. Never.

Iain Carter
BBC golf correspondent on Radio 5 Live

Matt Fitzpatrick was struggling a little and now that he's holed his first birdie out it can give him some momentum.

But get ready to turn your radio down.

Woods with back to back birdies - boy is he a fighter.

Yes! Matt Fitzpatrick joins the birdie train with a confident putt on the 10th, which did not look likely after that horror of a tee-shot.

The first splash of red on the Englishman's palette today and ensures he is back on even keel with St Andrews.

Next up is Woods for back to back birdies... got it!

Not quite the Tiger roar, more of a meow. But at least the big cat is stirring and making some noise.

Jon Rahm's driven the ninth green, but he's putting from a mile away, and he comes up well short.

Now, surely he won't three-putt for par (pros hate nothing more). But he does, leaving the birdie one short just to rub salt in the wounds.

Jordan Spieth got up-and-down from beside the bushes for his par, but considering how many birdies the ninth has presented today, that'll feel like a dropped shot for both players.