Postpublished at 00:47 British Summer Time 12 April 2015
Night! See you all tomorrow, I believe it's Aimee Lewis kicking us off.
Leader Jordan Spieth -16 (70)
Rose -12 (67), Mickelson -11 (67)
Hoffman -10 (71), Johnson -6 (73)
McIlroy -6 (68), Woods -6 (68), Casey -5 (74)
Use live coverage tab to watch up to five live streams
Radio 5 live coverage from 21:00
Aimee Lewis and Ben Dirs
Night! See you all tomorrow, I believe it's Aimee Lewis kicking us off.
Hi, I'm still here. Should Spieth win tomorrow, he will win Texas a 13th Green Jacket. The last was Ben Crenshaw in 1995. I don't know who the others were. Sorry.
Masters leader Jordan Spieth, speaking to the BBC: "If you'd told me I was going to make seven birdies today, on Saturday, when it's meant to be harder, I'd have called you crazy. With a lead you want to limit the mistakes which I didn't do so well but I grinded it out.
"I looked at the scoreboard very little today, not really until the end. I'll take the same attitude tomorrow. I'm not going to think about being in the lead. I've got two major champions behind me and it's not going to be easy but I'm in a position I'm happy with."
Sergio Garcia told us he and Tiger Woods would get along when they were paired yesterday. Our reporter John Murray said they barely interacted on the fairways but Sergio feels no beef...
World number one Rory McIlroy, speaking after it was noted he was the same age (21) as Spieth when he blew a four-shot lead going into the final round in 2011: "He's already experienced it once. I think he'll have learned from that and will definitely do better than I did."
I don't think we'll be hanging about for too much longer. Praise be for Jordan Spieth's double-bogey at 17, and I mean that in the nicest possible way...
Jay Townsend
Former American professional golfer on BBC Radio 5 live
"Justin Rose, not taking anything away from what a great player he is, doesn't have the intimidation factor Phil Mickelson has. Psychologically, and dynamically, it's a little bit easier for Spieth to play with Rose than with Mickelson."
Ian Poulter took to Twitter (again) earlier to tell us he "left a few out there" despite shooting 67.
The Englishman stands proudly at the top of the pile for finding greens in regulation today, hitting 17 from 18.
Phil Mickelson and Sergio Garcia come in second - hitting 15 of 18.
The strong man of the day is Jason Day.
His whopping 334 yard drive cannot be beaten but on average, Dustin Johnson is still the long hitter of this Masters with big blows averaging 321.67 yards over three days.
Where can Justin Rose, Phil Mickelson and their fellow Spieth-chasing buddies bring the lead down tomorrow? The par fives.
Statistically, they are the four easiest holes on the course, all four of them are averaging less than five blows. Dustin Johnson eagled three of them on Friday and made birdie at the other.
Kerry Thomas:, external Fabulous round, Justin Rose. Sleep well. We're all rooting for you.
Tom Maher:, external I'm sure Rory could give Spieth some useful advice on keeping a four-shot Masters lead.
Ouch. Rory McIlroy famously let a four-shot 54-hole Masters lead slip in 2011 before going on to win the US Open two months later for his first major.
Phil Mickelson, speaking to BBC Sport: "I had a lot of fun, this is the best scenario you can ask for as a professional golfer - you dream of playing late in the afternoon at Augusta and having an opportunity to win. If I can play a good front nine tomorrow, and that is my goal, I can hopefully be in contention on the back nine."
Ken Brown
BBC Sport commentator
"Jordan Spieth came through a stiff test with stunning colours. When he has been in a sticky spot he has managed to come out of it really well.
"His mental strength is amazing. He takes one stroke at a time and takes the good and the bad. It is about being patient, not taking any risks and he does that."
Justin Rose, speaking to BBC Sport: "The back nine was a lot of fun. The putt at seven really got things going. To finish like I did gives me a lot of momentum going into tomorrow.
"Jordan is playing flawless golf right now. It is a big lead but Augusta has a habit of throwing things up on the back nine so the key is to stay in contention going on to the back nine."
Spieth leads by four
-16 Spieth (US)
-12 Rose (Eng)
-11 Mickelson (US)
-10 Hoffman (US)
-6 McIlroy (NI), Woods (US), Streelman (US), Na (US), D. Johnson (US)
Selected others: -4 Poulter (Eng); -3 Garcia (Spa); -1 Scott (Aus), B. Watson (US)
Justin Rose has moved beautifully up the leaderboard today and his putting had much to do with the progression.
He was dead-eye, averaging just 1.44 strokes on the green - including one three putt. In the entire field, only Hunter Mahan was as good, also taking 1.44 blows on the dance floor.
Thank the golfing gods for those two charges by Mickelson and Rose, but for them it might have been a procession for Spieth tomorrow - and not great viewing. Ian Poulter of England matched their five-under 67s, which was the lowest score of the day.
Jordan Spieth is conquering...
His new mark of -16 means Floyd's effort in 1976 and Woods' in 1997 are consigned to the 'former record' bin.
... Spieth starts it a touch left of the hole and it obeys his command, ducking right and in - in it goes for a round of 70, -16 and a four-shot lead over Justin Rose in second. Hoffman follows him in for birdie and a 71, he's six back.