More from Jordan Spieth: "The greens significantly changed. On the back nine today that wind really dried them out. There was spots where they were crusty. If there is no water on them tomorrow it will be a bit ridiculous.

"Today was my learning experience for the week. It was really, really, tough to hold it together. When greens are crusty and they are that fast it is tough to make the two or three footers. It was a grind on each hole, emotionally it gets you going a little. I think the person who walks the tallest will win next over the next couple of days."

Leader Jordan Spieth on -4, speaking to Sky Sports: "It was a couple of strokes higher than I was looking for, par was a good score today. Playing holes 11 and 12 with two pars and also being couple under early, it was a couple higher than the goal. It was a bit disappointing but it is pretty much a new tournament coming our way over the weekend."

Hideki Matsuyama bogies the last, but is still one of the few players to get round the course today in level par or better. He started at one under, he ends at one under. Three off the lead.

Jay Townsend
Former American professional golfer on BBC Radio 5 live sports extra

"Spieth and McIlroy are both fantastic young players. I think that the only worry is they get caught up with each other and play against each other. There are a lot of good players out there."

Just joining us? Where have you been? The headline is this. Jordan Spieth leads Rory McIlroy by one shot. They'll play together tomorrow and you can watch it all on BBC Two from 19:30. It will be a belter.

I'm not entirely sure what Brandt Snedeker is getting at there. If you can shed any light, then please do.

If Jay Townsend is right, then no fewer than 32 players will sleep tonight thinking about handing in their measurements for a Green Jacket on Sunday evening.

Jay Townsend
Former American professional golfer on BBC Radio 5 live sports extra

"I think anyone within six shots is in with a chance over the weekend."

There are three groups still out on the course. Of all the players still out there, Japan's Hideki Matsuyama is the best-placed. He's two under playing the last. American Dustin Johnson is level and Justin Rose is in the pack on one over. The leaderboard is looking very congested.

-4: Spieth (After 18 holes)

-3:  McIlroy (18),

-2: Lee (18), Piercy (18), Matsuyama (16)

-1: Snedeker (18), Kjeldsen (18)

Selected others: Par: Dechambeau (A) (18), Lowry (18), Garcia (18), Willett (18) +1: Rose (14), Day (18) +2: Casey (18), Westwood (18) +3 Poulter (18)

Paul Casey is done too, a tough back nine seeing him come home in 40. 77 overall, five over for the day, two over overall. He's six off the lead.

Image source, EPA

Bryson DeChambeau's horror 18th is over with a seven. It was a day that promised so much, and even that blip on the last doesn't spoil what is a very good position. The amateur has gone round in level par and is even overall.

Image source, Getty Images

Jay Townsend
Former American professional golfer on BBC Radio 5 live sports extra

"It was a tough day. Spieth didn't give much away. He still has the lead. It is not really shooting yourself in the foot but he will be disappointed."

Excellent, excellent putt for Jordan Spieth on the last. Maybe as much as 15 feet. He's scrambles home in 74, a two-over round, one shot ahead of Rory McIlroy. Those will duke it out in a proper slobberknocker tomorrow. Spieth on four under, Rory on three under.

Image source, Getty Images

Bryson DeChambeau looks livid, as if matron has just told him he must have a bath this evening. His fifth shot (I think) is a chip from just off the front to past the pin. Two putts from there would be a result.

Jay Townsend
Former American professional golfer on BBC Radio 5 live sports extra

"Spieth has looked very edgy today. It is a day he will want to forget."

Image source, Getty Images

Spieth in the bunker. He'll do well to get this near the hole. A puff of sand, a skid on, at least 12 feet past. If he misses that, Rory McIlroy will have a share of the lead.

Jay Townsend
Former American professional golfer on BBC Radio 5 live sports extra

"That is a phenomenal result from DeChambeau. He played a massive high cut. He has got a shot to get it within ten feet of the hole."