McIlroy from around 20 feet on 14. This one's rapid. He backs off for another look before hitting.

It worked. It's in! What a putt. Oh boy did he need that.

Tied with Cameron Young.

Sam Burns can't follow McIlroy in so he stays one back.

Cameron Young has a makeable birdie putt and has just had a read off his playing partner Jason Day.

If this drops the American will have a two-stroke advantage, which was almost unthinkable earlier today. It's on it's way but he's pushed this too far left and it'll just be a par. Just.

Young signs for a superb seven-under 65, the joint best round of the day so far, with Scottie Scheffler.

Sam Burns from the first cut at 14. 121 yards in. Ohhh he lands it on the ridge and the ball feeds back down towards the cup.

It's such an inviting pin position, sitting in a little bowl. McIlroy pulls his wedge from 103 yards. The ball tries its best to meander back down, but that's pretty average from that distance.

Li Haotong with a couple of pars to steady the ship after that eventful run and he's just got one hole left to finish off a really good round.

I feel like I've said this a million times but Justin Rose has spurned another birdie chance with a short missed putt. It's getting to the stage now where I'm almost thinking I could do better.

Obviously I couldn't, but Rose has missed so many chances...

Iain Carter
BBC golf correspondent on BBC Radio 5 Live

This might be the moment because [McIlroy] has just hit the most extraordinary tee shot there.

I think all the frustration that has gone on around Amen Corner has just come out in that drive. He has just thumped that.

Shane Lowry has 252-yards to the pin from the fairway on the 15th so elects to take on the green.

But within seconds he wishes he hadn't as his effort heads right towards the bunker and flirts with the rim before travelling down and into the drink. An absolute shocker at this stage.

Tommy Fleetwood doesn't make the same mistake and lays up.

Great putt from Rory from off the green on 13. He lags it to kick-in distance and saves his par.

But he's gone six-four-five after that birdie on 10.

Sam Burns was clumsy with his third but he rolls in a beauty for his birdie and catches his playing partner, one back of Cameron Young!

Cam Young overturned a four-stroke deficit to win at the Players last month.

And now all of a sudden he is looking like the calmest man around Augusta National as he secures a par at the 17th.

This is a remarkable turnaround given where he was a few hours ago.

McIlroy has a tree in his way at 13. He's going to need to sling a draw around the bark and get back into a position where he can attack with his third.

After asking an official to move some wires, he scoots one out of the trees but he doesn't advance it as far down the hill as he would have wanted.

His third is 90 yards. It comes in low and fizzes through the green.

Nothing is easy right now. Such a stark contrast to 24 hours ago.

Justin Rose left himself in a stinker of a position over the back of the 13th green and his prod back onto the putting surface ran away from him a little bit.

However, and I've not said this once yet today, he produces a lovely putt to drain it for a third birdie of the day.

Patrick Reed follows him in as he finally gets his round under par for the day.

This is how Rory McIlroy came unstuck at the 11th. With so much space to bail out on the right, he hooked a seven-iron into the water and couldn't make his bogey putt after a decent pitch from the drop zone.

Shane Lowry dunks a putt in from 15 feet from the back of the 14th green. All of a sudden he's only two back. Could he be slipping into a green garment in around 24 hours?

The only good news for Rory McIlroy is that he's reached the scoring stretch of the back nine. Par-five 13, accessible pin placement at 14 and another par-five at 15.

But yet again, he finds the trees at 13. It's all going pear-shaped for the defending champion.

That's quite an incredible shot from Li Haotong, not in a good way either, as he's thinned the pants off his second shot to the 15th green and it's fizzed under the radar and bounded down into the water.

A chip and two putts later it's a bogey to drop him back to eight under as the mini rollercoaster he's on continues as he's gone bogey-birdie-bogey in his last three.

Brilliant from Tommy Fleetwood on the 13th. The Englishman has not had a great day so far but stiffs his wedge shot to around seven feet and then rolls in his third birdie of the day.

Andrew Magee
PGA Tour winner on BBC Radio 5 Live

Are you not entertained? This is what it’s all about.

Amen Corner has bitten once again.

McIlroy is starting to look really disgruntled now.

His delicate little chip from off the back of the 12th green is woefully short and he's struggling for par again. Nope, another putt fails to drop and Cameron Young is now the solo leader.

Sam Burns found the green but he can only nudge his birdie putt down to beside the hole.

Trish Johnson
Former Europe Solheim Cup player on BBC Radio 5 Live

What an extraordinary putt that was (from Cameron Young).

Plenty of right to left in it but he stayed down on it the whole time – that means the player is really interested and they know he’s got every chance.

What a comeback birdie.

Cam Young sinks a 27-foot putt for birdie. He moves into a tie for the lead.

On Thursday, he was four over after seven holes. This is some performance.