Is Niall Horan down there? The screaming, whooping and hollering makes the 10th tee sound like a One Direction gig.

McIlroy is still zoned out in Rory world, mentally locked into what lies ahead.

The next task is a putt on the 10th green. He's driven it but the ball is so far away from its destination most of us would need a taxi to get there.

Showing a few signs of tension, however, is Hovland. He grimaces after going right.

"All the wrong angles down there," muses Sir Nick Faldo.

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

Viktor hasn't taken many of the chances he's created. He has to stay in his own zone and try and chip away and make that gap bigger as he goes on.

McIlroy now taking every care to make sure he doesn't give a shot to the field now.

Scottie Scheffler enjoys his very first birdie of the day on the 10th to get back to nine under and two over for the day.

It all came from the cold start with the putter and he's just not been able to get anything going since then.

Can the Camerons keep their foot on the gas?

Smith's certainly intending to anyway as he sweeps a glorious mid-iron into the 11th green. Fifteen feet or so for a birdie.

Young's about a club out and he'll have another long putt.

Alex Bysouth
BBC Sport at St Andrews

An ear-piercing squeal of excitement from one fan up near the 10th green and 11th tee will have informed Rory McIlroy and Viktor Hovland that Cam Smith just went very close with his eagle attempt, echoing all the way down to the ninth green. It’s soon replaced by cheers for the leader and chants of “Rory, Rory, Rory”.

-17 Rory McIlroy (9)

-15 Viktor Hovland (9), Cameron Young (10), Cameron Smith (10)

-13 Dustin Johnson (12)

-12 Jordan Spieth (13), Tommy Fleetwood (12)

Full leaderboard

Ohhh that's a beautiful chip from Cameron Smith on the 10th, using the slope to feed his ball down to the cup.

A certain birdie by the look of it. Yes sir!

Young's faced with a 100-footer from the back. Up it comes over the ridge. It's trying but it just doesn't have enough pace.

He needs to make this one, and no mistake! Birdies for Young and Smith and they're keeping the pressure on the leader.

First up is Hovland and again he leaves himself with too much to do with the putter.

Rolls close but never looks like dropping.

Over to Rory... lipped out! The birdie putt clips the side of the cup and that's another missed chance.

Out in 35 for the Northern Irishman and he's two clear. But it could have been oh so much more.

Back on nine, Hovland and McIlroy avoid the fate suffered by Cam Young.

Hovland finds the first cut and his approach again doesn't trouble the hole to much. Half a chance though.

From the fairway, McIlroy has a better route in and sticks a half-wedge within birdie distance.

Apologies to Adam Scott for a classic commentator's curse after saying not to rule him out after 11 holes, after 12 holes we can!

He has to reload on the tee after a wayward drive to the right and that results in a double-bogey six to drop him back to 11 under.

Big drive this for Cameron Young after visiting the gorse on the ninth.

Oh that's a much, much better effort, and while his ball skips on towards the back of the green, he'll have a long putt for an eagle as he looks to bounce back from a bogey for the second time today.

Smith's hit a belter, too, and he's just shy of the green.

While not the start which Viktor Hovland wanted, he's only made one real mistake so far.

You feel he's got more gears to go. Whether he can find an extra one, especially with the whole of St Andrews willing on his playing partner, remains to be seen.

All slightly conservative so far.

Lydia Hall
Ladies European Tour winner on BBC Radio 5 Live

Unfortunately for Cameron Young his ball was hanging in the branches of a gorse bush.

I have to say though, the shot by Cameron Smith was beautiful to come in and get his birdie putt, holing out for par - but a change in fortunes for the Camerons.

Cam Young pays the price for an errant tee shot that found the gorse bush and slips back to -14.

And there are more groans from the crowd as Smith watches his birdie putt slip past.

Opportunity missed there.

Alex Bysouth
BBC Sport at St Andrews

As Rory McIlroy was taking his birdie putt on eight, world number one Scottie Scheffler was walking up to the 10th green and, without checking his stride, having a good look at how the leader was faring. The putt didn’t drop, a feeling Scheffler knows well today, despite making his own birdie effort on 10.

Dustin Johnson boasts a lovely clean card today.

The two-time major winner records his third birdie of the day on the par-three 11th and moves to -13. Quietly creeping up...

Cameron Young is forced to take an unplayable on the ninth.

He drops left of the gorse and is playing his third. He does well to pop it up onto the green but it'll be around 20 feet or so for a par - on a hole that has been giving up birdies and eagles by the bucket load all week.

Cam Smith's stress levels are much lower. He flops a nice wedge onto the surface and he'll have the chance to move to within two of McIlroy.

No room for error when the stakes are so high and no danger of these two making a mistake here.

Tap, tap, tap it in.

That's what both men do from close range and stroll off to the ninth tee with their chins pointing upwards.

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

The one thing that I am really impressed with McIlroy with - we know he can play aggressively - but he's been really conservative today to give himself the best chances for birdies.

This green really lives in its own postcode.

Hovland goes first and a 70-foot birdie putt acquaints ball with hole wonderfully.

Up the slope it goes, sticking on the brakes to the left side of its new neighbour.

Less distance for McIlroy but a trickier path in. Ball veers right then straightens up, ending up just short of Hovland's marker.