Patrick Reed's best finish at Augusta? Tied 22nd in 2015. The American didn't even make the cut last year.

That Rory McIlroy birdie has applied the pressure though - how can Reed respond?

Completely unfazed. He steadies his putter, takes one last glance at the hole and then slides a nine-footer right into the cup for a nerve-settling par.

Stenson up the hill on 18... good pace, good line, should escape with a par.

Over to Rory... he's not missed much with his putter today. Can he sink one more? Yes! Another superb putt from the world number seven moves him to 11 under.

McIlroy has an explosion of emotion, fist-pumping and embracing his caddie. Back to Patrick Reed and that testy par putt...

Patrick Reed is playing blind here. He can see the flag, but there's no sight of the green surrounding it.

No problem for the 27-year-old Texan. A little sliced clip on to the good stuff that digs in and anchors nine feet from the flag.

He's playing like a champion.

Peter Alliss
BBC Sport commentator

Young Master Reed could do with a bit of magic here. He needs a little check of his map. Make sure you get the right hole.

Make the most of this stroke of luck please Mr McIlroy. Think Paul Azinger was joking when he said it was a squirrel, but who knows? Augusta is a magical place where strange things happen...

McIlroy pulls a mid-iron out of the bag, swishes one towards the green and starts walking after the ball with club in hand. That's when you know he likes it.

He's up on the top deck and 17 feet away from a fifth birdie of the day. Knock this in, Reed drops one, then it is game on...

Paul Azinger
1993 PGA Championship winner from Augusta

Patrick Reed could not have put it in a worse spot to try and get it up and down. I don't think he knows how far over he's gone. It's a diabolical green with all sorts of humps and mounds.

How's this lying for Patrick Reed? His tee shot went right, finding the straw beneath the canopy of the pine trees.

He slaps it up towards the green. The American overcooks it, getting a little too much on his approach, and it kicks on beyond the green.

Paul Azinger
1993 PGA Championship winner from Augusta

A squirrel up there tossed that right back into the fairway. Great break there for Rory.

Wonderful dink from Dustin Johnson on the last, that should be a simple tap-in for a par. Rory McIlroy is on the tee behind him.. uh oh. A devilish slice sees him heading towards the trees...

Fast forward again and Johnson's playing partner Jordan Spieth misreads his birdie putt. The 2015 champion refocuses to par and sign for a one-under 71.

It feels like the entire population of the Augusta patrons are following the Patrick Reed show.

There's a twist in the tale at 16 though... the Georgia faithful's new-found favourite cast member finds the 16th green from the tee, but proceeds to three-putt.

Bogey.

The leads slips to four.

Rory McIlroy's sizing up a shot from the rough like he's landed it in a children's playground. A whole lot of bark cast across the floor of the woodland around the 17th fairway.

He prods it out and narrowly avoids the sand, before coaxing his third shot to within an arm's length of the flag.

The Northern Irishman taps in for par.

England's Justin Rose after carding a one-under 71: "It's been the most frustrating day of the week for me. We got lucky with the weather, we were expecting a day when we had to battle hard. But the course opened up, we could get some iron shots close and I was looking at the leaderboard, seeing some good scores and I was aware of that.

"I made a good run about 6 and 7, had a good chance at 11 and didn't get the ball up and down at 12 and 13. that's where I lost momentum.

"It's looking like I will be quite a few back going into tomorrow and I would have liked to have been a handful closer.

"It's a golf course you can have a big comeback on and on the Sunday the pins offer an opportunity to shoot in the low 60s. I'm surprised more guys haven't had comebacks here - let's hope that starts tomorrow."

Patrick Reed chops his tee shot straight on to the 16th green, but it fizzles away from the pin and picks up some speed down the slope. Is it heading for the water? Not quite.

Wow.

That's remarkable from Patrick Reed. Everything he touches is turning to birdies, but this time it's even better... the American chips in from a slither of grass between the bunker and the water to eagle from 27 yards.

Only two shots ago he was tucked up behind a pine tree and we were speculating whether this would be his undoing.

Twenty minutes later and he leads the Masters by five strokes.

Two-time Masters champion Bubba Watson on his four-under 68: "It wasn't good enough - Patrick Reed has gone crazy out there! No, seriously, it was good for me to get into the 60s - I'll take that anytime in a major championship.

"The first seven holes are very difficult but if you get under par quickly and get some red numbers then you can shoot a low score.

"I've got to shoot seven or eight under to scare them."

Nervy? Not for Rory. Slightly uphill, left to right, judged to perfection.

Oh, what's that noise? An ear-deafening roar goes up from somewhere behind McIlroy...

A delicate touch required from McIlroy on 16... the ball fizzes out of his wedge, checking as it hits green and rolls towards the hole. It goes past the right lip and then sticks on the brakes with the slope looming. A nervy one back...

Patrick Reed has his club head between his hands, turning it left like he's trying to direct his flighted approach on the 15th with a joystick.

It just beats the water hazard and drops narrowly short of the now-sodden sand. He can see the flag, 27 yards in the distance.