Oh no! Cameron Smith's approach at the seventh takes a firm bounce and he must, like Young, negotiate the slope.

Young's putting for a two, though.

Staying in his own little world was the McIlroy mantra and so far it is paying dividends.

The spiritual power is evident at the moment. No befuddlement in his brain.

We see that illustrated on the par-four sixth where, after driving to 60 yards of the pin, McIlroy pulls out the putter. That's right!

It's a difficult chip with not much of a landing pad, so out comes the short stick to navigate the slopes.

What a touch! McIlroy runs after it for two reasons: one because he loves it and two because he wants to mark it before it comes back down the hill.

Cameron Young leans left. That means his drive at the seventh is leaking right.

Shell bunker's over there! Oh wow, his ball skips gleefully past the lip of the trap and bounds onto the green.

And incredible result. Or is it? He's got to be close to 80 feet away and with a huge mound between his ball and the flag.

Will he pull the wedge out of the bag for that one?

Lydia Hall
Ladies European Tour winner on BBC Radio 5 Live

The Camerons' balls were sat down heavily in the rough and they couldn't attack this pin. Missed fairways cost them both a chance on this hole.

Alex Bysouth
BBC Sport at St Andrews

Both players are met with a smorgasbord of phones being thrust towards them on the tee box.

But Rory McIlroy remains as chilled as the river lapping the shores of St Andrews’ Eden course next door, sipping some water from his flask as he bounds down the fairway with that trademark bounce.

Cam Smith demonstrates that silky putting touch from the back of the sixth green and gladly takes his par.

Now then. Young three-putted from distance on the first and has put himself under more pressure after leaving his long birdie bid six feet short.

But in it goes! Clutch.

Italy's Filippo Celli took his entire family (well, his mum and dad) to the BBC Radio 5 Live interview booth after finishing with a one-under 71 to take the Silver Medal prize as low amateur this week.

Mrs Celli could not hold back the tears of pride.

Listen to live commentary by clicking the link above.

Image source, BBC Sport

Former Masters champion Adam Scott is playing beautifully under the radar and at 12 under after three birdies today he's not a million miles away.

Rory's got a nice lead right now, but we all know that just one bad shot around here can cost you plenty of shots - so the chasing pack still need to get into position.

Scott is playing as well as any of them.

Matt Fitzpatrick is just two shots further back after a quiet round with just one birdie today.

Iain Carter
BBC golf correspondent on Radio 5 Live

You can hear for what the St Andrews crowd thinks to that as Rory taps in for his first birdie.

The stands are jam-packed behind them, but Hovland didn't do enough and taps in for a prosaic par five.

Vital clear light for McIlroy.

The Camerons both draw heavy lies in the rough on the sixth, and while they muscle their balls onto the green, neither will be expecting to hole their lengthy putts from way beyond the pin.

Take your pars and move on, lads.

All aboard! The McIlroy train is leaving the station. The eagle putt doesn't drop, despite the thousands around the green willing it to disappear.

No worries. He's assured of a birdie and knocks that in.

The heat turns up on Hovland, who is putting for birdie. That slithers past and McIlroy extends his lead to two shots.

The Road Hole claims any lingering hopes from Xander Schauffele after he hits his ball into the most infamous bunker in golf.

In fairness, he did really well to get the ball out, somehow engineering a stance by almost absorbing his backside into the revetted face of the trap and somehow thumping it up and out onto the green.

It was impressive shape-shifting but after missing the par putt, that's that for Schauffele.

Alex Bysouth
BBC Sport at St Andrews

It’s cooling down out here but hotting up on the leaderboard, a breeze is picking up and so is the level of anticipation from the Rory fans lining the Old Course. A huge reception as he strides on to the fifth green, sprinkled with encouragement for Viktor, too.

McIlroy drives into the first cut on the fifth - this is where the party started for him yesterday.

He stands back after hitting his second and watches intently as his ball soars towards the green. Surefire sign he likes it.

Lovely line. What about the length? Oh yes! A hop and roll forward leaves him 15 feet or so from an eagle.

Hovland needs to respond... to that shot and to his bogey on the previous hole. Oh, and to having to knock out of the rough to safety.

Down below the Spectacles bunker, he can't see the green - which is quite apt.

Nevertheless he pumps up a mid-iron and is putting for a birdie.

Tommy Fleetwood, second to Shane Lowry at Royal Portrush in 2019, is quietly going about his business today.

Two under through six, Fleetwood knocks his approach at the seventh in tight and strokes home for another bird.

Both he and Dustin Johnson are gearing themselves up for a big back-nine charge. I can feel it.

When this heatwave kicks in I'm using Scottie Scheffler's putter to cool my house down, as it is stone cold right now - we're talking artic temperatures as he misses another par putt.

Back-to-back bogeys means it's goodnight Vienna for the world number one.

Cameron Smith looks away in disgust as his drive on the sixth ducks into the rough on the left.

Young's in there too. They'll have their work cut out for them.

Lydia Hall
Ladies European Tour winner on BBC Radio 5 Live

Smith knows that was super important not to let that one get away here.

It drops in for Young too.

That pressure on the final group is building up.

-16 Rory McIlroy (4)

-15 Viktor Hovland (4)

-14 Cameron Smith (5), Cameron Young (5)

Full leaderboard

Mamma mia! Filippo Celli is dressed like Filippo Inzaghi today. He's wearing an Italian football shirt.

Standards are slipping in the enforcement of the R&A dress code.