Concerned murmurs from the crowd on the ninth tee as Cameron Young hooks a horrible looking drive into the bushes.

Lap of the gods.

Cam Smith holds his finish. Yep, that's in much better shape and he'll have a flick with a wedge coming up as he chases another birdie.

On to the eighth tee... the first par three of the Old Course awaits.

McIlroy's honour and the boisterous shouts seconds after he makes contact indicate good things.

Or it indicates the fans are getting oiled. Maybe both.

Difficult pin position again here, with the flag sitting proudly on a little natural turret.

McIlroy is on the green but below the pin, with Hovland going to the left.

Massive green, massive birdie putts for these two.

Alex Bysouth
BBC Sport at St Andrews

We’ve hit that spot on the course where it’s a punter’s paradise - get a good spec on the loop and you can watch it all.

Cam Smith in one corner, Rory McIlroy and Viktor Hovland in another.

And Tommy Fleetwood too… a rendition of “Tommy, Tommy, Tommy…” goes up for the Southport slinger on the 10th green.

Let's not rule out Adam Scott just yet after a birdie then superb par save means he's on 13 under and not too far away at all.

I never like those long putters when you have to really hit the ball, and Scott will have hardly had to have taken a bigger swing than to get his ball up this mountain at the back of 11.

He rattles it up there though, knocks in the par putt and moves on - four behind McIlroy.

Lydia Hall
Ladies European Tour winner on BBC Radio 5 Live

Both Camerons both had a bit of work to do to save their pars.

McIlroy will be keeping a close eye on that leader board to see if he needs to be more aggressive going forward.

Can Cameron Young keep his excellent progress going?

Oh yes he can! Another putt finds the bottom of the cup and that's a huge par save for the American.

Cam Smith has a tricky six-footer for his par, too. Makes it!

Keeping the bogeys off the card. It's the most important thing for the chasing pack.

Alex Bysouth
BBC Sport at St Andrews

“He’s putting it!?” a few punters on the sixth voiced their surprise.

They didn’t expect to see the flat stick appear from McIlroy’s bag a little earlier.

Worked out alright, eh? Not put a foot wrong yet.

Another show of lag-putting from the penultimate pairing, this time on the eighth.

Hmmmm, they both leave themselves with a fair bit of work to do for par.

And with Rory watching closely back on the tee. Big moment coming up.

Simon McCormick: If Rory can win this, you suspect he could suddenly go on a run of Major wins in the next few years.

Good point this from Simon, as McIlroy has been knocking about at the top of major leaderboards all year and he did win his four majors in the space of three years and 15 tournaments.

He also won two back-to-back in 2014 with The Open and PGA Championship - and if you want more then that year's Claret Jug was claimed at Hoylake, which just so happens to be hosting The Open next year..

From below the stage which is hosting the hole, McIlroy will be aiming to get close enough for a simple par putt.

The long putts have so far today been wonderfully-judged by the Northern Irishman.

So too is this one.

Hovland has 35 feet for a birdie... he really could do with this. No, that's not dropping. Little has yet for the Norwegian.

Pair of pars and on we go.

"Down!" That's Viktor Hovland pleading with his ball on the seventh.

From the wispy rough, he plays over the Shell bunker guarding the green and goes past the hole.

Probably as good as it gets from there.

We see his playing partner sussing out his shot up ahead and don't panic McIlroy fans.. he's well short of the Shell bunker.

McIlroy lobs up a high ball which then hits the ridge - and bounces off left.

Cue groans.

John Murray
Commentator on BBC Radio 5 Live

What a run Young is having here. This is his reward for finding the green from the tee. It took a 360, had a look all around that hole and it dropped in.

A fourth birdie in five holes - and all of that after he dropped a shot on the first hole.

A bit of breaking news... the tweet below is from Press Association golf writer Phil Casey. Looks like Sergio Garcia's Ryder Cup career could be over...

Garcia is, of course, one of the golfers who has joined the LIV Golf setup and has been suspended from playing PGA Tour events.

-17 Rory McIlroy (6)

-15 Viktor Hovland (6), Cameron Young (7)

-14 Cameron Smith (6)

-13 Adam Scott (10)

Full leaderboard

Cameron Young just needs to get his 88-foot putt to the edge of the slope and let the contours do their work.

And he's measured that one beautifully. A short birdie putt coming up for the American.

Can he join Hovland in second? Yes he can, the ball does a full 360 around the cup but down it goes!

Smith nudges his birdie effort down to beside the hole and will stay at -14.

Four birdies in five holes for Young. He's looking like McIlroy's biggest challenger at the moment!

Jordan Spieth bounces back with a birdie on 10, but just slides another birdie try down the left on the 11th.

He's certainly playing well enough to post a decent number here but he's going to have to make everything down the stretch and hope for a collapse up front.

Hmmm. Almost jinxed it.

Rory McIlroy lamps another drive out of the sweet spot but his boldness may have left him in a spot of bother.

Might be getting some sand on his spikes.

Hovland doesn't have as much power off the tee and doesn't quite go as far on the short par four.

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

That was a great effort from McIlroy with the putter.

It took forever to watch the ball go up then down, and then come back up. It was a great opportunity for a birdie but heart in mouth moment.

It is great to see players use their imagination - it's fun to watch.

Another hole, another birdie chance. Pretty sure McIlroy has hit every green in regulation so far.

The knees bend as his birdie putt rattles towards the hole, but the groans tell us it just misses.

Tick it off, another par. Another step towards the Claret Jug.

Don't say it, don't say it, don't say it... *whispers* McIlroy is so in the zone it is hard to see when and where a mistake will come.