Alex Bysouth
BBC Sport at St Andrews

Corr. Now that was a roar! The sound seemed to funnel across the Old Course like a stampede as the crowd gradually realised Rory’s effort was dropping. “Eagle!?” quizzed punters who couldn’t quite see what happened. Landed, my friends.

Hovland, trying to keep his cool after the almighty roar that greeted Rory's masterful bunker shot, putts from below the 10th green.

He gives it a chance...oooh, not quite. It zips past and he'll have around 12 feet to join McIlroy at the top.

He makes it! The ball disappears from the left edge and we have a two-way tie at the top.

Glorious golf by these two stars.

John Murray
Commentator on BBC Radio 5 Live

What a noise at the 10th for McIlroy - and he's holed a bunker shot to take the lead.

That is extraordinary from this young golfing superstar.

The good news for Rory is that his ball has settled in the middle of the bunker on the 10th.

He steps back, not once but twice, after hearing a ripple of applause over his left shoulder.

Now he goes. He gives it good thud. It looks good...it looks PERFECT!

In it goes for an eagle. WOW. McIlroy leapfrogs Hovland and takes the lead - amazing!

Onto the final stopping point of the front nine for the final group.

This short par-four represents an excellent chance of a birdie.

Especially when, like Cameron Smith, you drive the green.

Alex Bysouth
BBC Sport at St Andrews

This could be some shootout down the back nine. And just imagine the excitement if this is the final pairing tomorrow…

John Murray
Commentator on BBC Radio 5 Live

We have learned already that you must not take your eyes and ears off Hovland, but he misses.

I love the way that he doesn't mess about. Hovland is a man of business.

There is a roar of encouragement for McIlroy.

Great entertainment this - won't it be great if these to play tomorrow as well.

Oh no. McIlroy loses his drive on the 10th to the right and it's gobbled up by a coffin bunker. He looked a bit fast through impact on that one.

Hovland nails one. It skips past Rory's bunker and settles just shy of the green. Advantage Viktor on this hole.

-14 Viktor Hovland (9)

-13 Rory McIlroy (9)

-12 Dustin Johnson (10), Cameron Smith (8),

-11 Patrick Cantlay (11), Scottie Scheffler (10), Cameron Young (8)

Full leaderboard

Birdies for both of these on 10, which is another hole there for the taking - even if it's a bit scrappy from Scheffler.

It means Johnson now moves to 12 under and just two off the lead without too much fuss.

Still the birdies putts keep on coming for Patrick Cantlay.

This time, it's a long one and doesn't trouble the hole.

Outside chance of a birdie for Cameron Smith.

Yesterday it would have been a good chance, but today it seems someone has replaced his putter with a poker stick. And it's a cold one.

Never looks like stoking the hole and another par will have to do for the Aussie.

Seven straight pars after that opening bogey.

"Go on, go on!" The gallery urges Rory's eagle putt down to the hole. It tries its best to make it, but comes to a stop about four feet short. A tester.

Now it's Hovland's turn. We know how deadly he's been over these long putts, but he's raced this one miles by! A rush of blood to that young head of his.

Ooooh, the one coming back stays above ground as well! A rare error from the Norwegian.

The door is ajar for Rory. This to move to within one - he gets it!

Lovely touch. Like a butcher cleanly slicing a wafer-thin cut from a leg of ham.

Cameron Young is in the rough and looks a nasty little shot.

But he uses his wedge like a carving knife, cutting the grass out of the way and letting his ball drop neatly towards the hole.

Tasty shot and should see him snaffle a par.

It's Hovland's turn to have a belt at the ninth.

Oh hello, it's not quite as close as Dustin Johnson's, but it'll still be a look at an eagle.

McIlroy's out with the chief. That's a lot of club for him, but he cuts a high one in that lands softly on the apron and rolls out to around 50 feet from the pin. Great hitting from these two!

"Go on Cam!" is the shout from those around the eighth tee.

That's the beauty of this group, you can just shout your support once and both players will get a boost.

Smith goes first on the front nine's only par three, sashaying onto the the dancefloor with one of his best moves.

Let's see if Young is going to join him? Nope, he's a bit shy.

The American tries to float one in high, but the wind grabs hold of the ball and he falls short.

Looks like he's in the rough, but might have been lucky and perhaps it has popped out.

Image source, Getty Images

Johnson's eagle try is a nice one - in typical fashion he's trying to coax it in dead weight rather than jam the ball in at pace, but as such it just goes for a late walk to the right and misses by a whisker.

A birdie then for DJ, and 'only' a par for Scheffler who misses a straight one and that'll feel like a dropped shot on this hole.

They both turn in 34 and still right at the sharp end of this tournament.

Alex Bysouth
BBC Sport at St Andrews

A huge rendition of “happy birthday” rings out from the grandstand at the 11th tee for Adam Scott. Nice!

John Murray
Commentator on BBC Radio 5 Live

Hovland and McIlroy have had to wait because there is a bit of a log-jam now and a couple of pars would be a very good outcome as they go through hole eight.

And Hovland was able to take a quick look at the leader board - he knows exactly where he is.

Alex Bysouth
BBC Sport at St Andrews

The same small plane has been circling the skies above the Old Course all week - if I knew more about planes I’d tell exactly you what type it is… three wheels, two wings, some sort of engine? Anyone?

Anyway, that’s a very convoluted way of saying whoever’s up there has a great spec.