Image source, AFP

Still birdies to be had down the stretch but Spieth's challengers are melting away. McIlroy with a peach off the tee at 16, Tiger has missed the green. Spieth into the heart at 14, although he's appalled by the result as his ball dribbles away to the right of the flag, which is a very good sign for the future. Rose has a very makeable birdie putt.

Paul Azinger
Former United States Ryder Cup captain and BBC expert

"Normally putting cross-handed, looking at the hole is something you do when you have the 'yips' of some form. But he has made more birdies than anybody in the history of this event."

Peter Alliss
BBC Sport commentator

"Spieth had a bit of fire in his belly but he is calm. But you do see him sometimes, he talks to the ball, talks to his caddie, give the thumbs up. He has got the enthusiasm of youth and skill beyond his years. He looks a dodgy putter, he is cross-handed, looks at the hole from a short putt, all things people that are having a bad time putting do, to putt better."

Image source, Getty Images

Rose made birdie at 14 yesterday, he could do with another today. He's given himself a chance courtesy of a barnstorming tee shot. Spieth going with driver... only the third time today he's gone with the big stick and it's a pretty good result, although into the first cut. Woods at 15, pretty good, he taps in for birdie to get to six under. McIlroy, too, makes birdie to get to -11 and outright fourth. Mickelson three-putts 14, drops to -12...

Steven Davison: That shot just won Spieth the Masters!!

Harry Cornwell: If Tiger Woods made more fairways this weekend, I think we'd be seeing a joint lead at the moment.

Tom Watson: Spieth is not only the best player this week but the luckiest. You can't play against this.

Paul Santaana: Missus watching some chick flick, so keeping up with play on my generic tablet device and a cold beer.

Image source, EPA

... no eagle for Spieth on 13, he'll tap in for birdie to move to -18, which matches Woods's finishing tally in 1997. Rose, too, makes birdie to move to -13 and into a tie for second.

Image source, AP

Mickelson's second at 14 is pretty ordinary, he'll need a miracle to make birdie from down there. Dustin makes double at 16, drops to -8. McIlroy with a six iron into the 15th, that's pretty decent on the back of the green. Spieth has a putt to go to 19 under, one better than Wood's finishing total in 1997...

Image source, AP

Mickelson crashes his drive down the 14th, as McIlroy does much the same up on 15. Woods got a birdie here yesterday but that's another missed fairway, although only in the first cut. Spieth conjures a magical approach at 13, right at the flag and the skinniest part of the green. Rose not far behind him, two majestic efforts.

Image source, Getty Images

Spieth has made three birdies this week at 13 and he's spangled one down the middle today. Rose missed the fairway, I believe. McIlroy at 14, ramming one up the hill, he'll make par coming back. Mickelson gets to 13 under par courtesy of birdie at 13, he's now only four shots behind. You never know...

Currently one under for his round, Spieth needs to pick up two shots to take the record outright.

Image source, Reuters

Mickelson for eagle at 13. That's pretty decent, but he's still got a six or seven-footer for birdie. Spieth's par putt skips over the cellophane bridge, he falls to -17. Still, that's a lead five shots. Dustin is swimming at 16...

Mickelson into 13, twirl of the club, on she goes. Spieth with a sneaky putt downhill at 12... bit heavy-handed, will do well to make par from there. Rose's birdie effort at 12 stays a foot right, he stays 12 under.

Image source, Getty Images

Hunter Mahan is the clubhouse leader on eight under, by the way. Matsuyama with a birdie chance at 15, to get to -11... misses left. Dustin can only make par at the par-five 15th, stays -10, tied for fourth.

OUCH: As a four-year-old Texas Rangers fan, Spieth attempted to catch a stray ball at a game, lost it in the lights and had his two front teeth knocked out.

Image source, Google

Peter Alliss
BBC Sport commentator

"It sounds ridiculous but it has gone a bit flat, Spieth has been magnificent and we were expecting a bit more from the chasing pack. Spieth has been so calm, his eyes are calm."

Image source, Getty Images

McIlroy's eagle putt at 13 slides by, he'll make birdie to get to 10 under. Spieth at the par-three 12th - tells it to sit down, and it does. I wish my balls were as obedient as his. Rose, too, parachutes in to the centre of the green.

Image source, EPA

Spieth on 11, chipping on, that's glorious, will make par from there. Not often you see a man so young rise to the occasion as well as this, this is as ballsy as it gets from Spieth. Woods bends in that eagle at 13, taking him to level for the day and six under for the week. Pars for Spieth and Rose at 11...

Andrew Cotter
BBC Sport commentator

"There is fierce competition going on behind Jordan Spieth for the minor places but it would take a feat of epic proportions to catch him."