Up ahead of Scheffler and Hatton is Dustin Johnson.

Last thing they want to hear drifting back is a roar which tells them the co-leader has dropped another birdie.

There is a birdie among that group - but it is for Marc Leishman, who is still scrapping against the Old Course.

Johnson knocks in a par putt and stays on eight under.

Alex Bysouth
BBC Sport at St Andrews

More on the trouser watch front, John Daly is just taking a few final putts before he heads out and is sporting some orange Hooters pants. Unique.

Next up for this trio? The Road Hole and that tee-shot.

Can Jon Rahm finish his front nine with a bang? Ahh, not quite as his eagle try from the back of the ninth green lacks pace.

Still though, that's another birdie and it sees him out in a tidy 32. Smooth.

Jordan Spieth was a little heavy-handed with his second but he's got the putter working today. Another one rolls in and he matches Rahm's 32.

Can Harold Varner III make it three 32s? He certainly can! This three-ball had their struggles yesterday but they're sailing through this second round, and it's making for highly entertaining viewing.

Image source, Getty Images

Dustin Johnson is not one for slow play...

Something has amused Tyrrell Hatton and Scottie Scheffler. Maybe it's schadenfreude at seeing Joaquin Niemann putting from somewhere near Dunfermline.

Jokes, they wouldn't be so rude.

Good effort from the Chilean, putting up from the front of the green but still leaving himself with a longish par putt.

Back to the birdie hunt... Hatton goes first... good pace, decent line... veers off left at the last few seconds.

That gives Scheffler, coming from a similar angle, something to think about.

The world number one decides to aim just out right after seeing Hatton's putt... and, of course, it stays out there.

If you're having your lunch watching the golf, why not take a look back through our Open archives and watch the great man himself in action, as Seve Ballesteros shows his brilliance to win the 1984 Open Championship.

Patrick Cantlay is four under after eight holes, and he's just hammered a tracer bullet off the ninth tee that's settled beautifully on the green to give him a serious look at eagle.

On the 16th, Scottie Scheffler swings his wedge with some venom after his approach.

Not sure what he is so unhappy about. Ball pitches just short of the pin, hops, skips and spins back to about 12 feet.

Maybe he wanted more backspin.

Hatton next... he goes slightly more left. Think he's happy with that.

Both have birdie putts for a share of the lead.

Who wouldn't be happy with an opening 66 at The Open?

Rory McIlroy was delighted with his game, but it's his attitude and patience that has so many believing he can win the Claret Jug again on Sunday.

A great move from Sergio Garcia today, who got to seven-under for the day before a bogey at the always-difficult 17th stalled his progress.

The Spaniard - who has a bucket load of top-10s in this championship over the last 20 years - is unable to reclaim that dropped shot back on the 18th but he's round in 66 and will safely make it through to the weekend.

Image source, Getty Images

Tyrrell Hatton has been landing punches on St Andrews like his namesake Ricky did on 00s welterweights.

Can the Old Course give a jab back to the Englishman? Hatton (that's Tyrrell) has a tricky putt off the side of the 15th green, aiming way out right and using the contours to arc the ball round.

Beautifully judged. That leaves a short one for par and he stays on seven under.

So does Scottie Scheffler, who knocks in 10 footers like they are open goals.

Image source, Getty Images

Fiztpatrick picks up another shot on the ninth after a laser of a drive almost resulted in him grabbing an eagle. He's well placed though halfway through his round.

Tiger Woods less so, after again a birdie putt just slides the wrong way. You know, as bad as it's been for Woods he's had chances on the greens and with just a slightly warmer putter he'd have a fighting chance of making the cut.

Yes, the ninth does indeed present a great opportunity, Mr Murray, and Jordan Spieth looks poised to take advantage after uncorking a cracker of a drive to the back of the green.

Jon Rahm smokes one too - ohhh that's fantastic, trundling up the green and rolling past the pin before eventually nestling up against the back fringe. That's a very makeable eagle putt coming up for the Spaniard!

So many players are making moves today. This is The Open at its best.

Image source, Gett

Andrew Murray
BBC Radio 5 live commentator

Very intelligent, patient, calm and he looks in control of what he's doing. Spieth has a great opportunity at the ninth hole. He is going to be right there at the end - no question.

Alex Bysouth
BBC Sport at St Andrews

Ian Poulter’s fancy speckled kecks must be a touch on the snug side today, the Englishman spent his whole walk down the second fairway trying to adjust them. It’s a long old hike with trousers that don’t fit comfortably.

Image source, Rex Features

It is about to change...

Young and Johnson! Sounds like a 60s folk band. Or a pharmaceutical company.

But they are new co-leaders.

You know that long birdie putt we mentioned? Dustin Johnson just made it look like a tiddler. Never left the centre of the hole from the putter.

Cameron Young has been out on his own at eight under for the best part of 24 hours.

Is that about to change?...

DJ has been playing some of the hits today, but goes safe on the 16th. One which won't get the crowd going wild, but getting them nodding their appreciation.

Heart of the green for two. Long putt for a birdie though.

Adam Scott missed the dancefloor but still has the broom putter out - despite being close to the rough. Good effort and leaves him within touching distance of the par.

Graeme Storm
Two-time European Tour winner on BBC Radio 5 live

Just a majestic effort from Tyrrell Hatton - it's just a tap in birdie now but he is making a great charge up the leaderboard.

Image source, gett