Right, that's it from us after an extraordinary day's cricket. We thought we'd been treated to a thriller when New Zealand scraped past Australia, but that really was something else from England.
Join us tomorrow for the not exactly small matter of India-Pakistan tomorrow afternoon. Until then, goodbye.
Get Involved
#bbccricket
Post update
Vic Marks is absolutely right about the effect on the group table. England would have been out of it if they've lost, but now they're in with a real chance - if they beat Sri Lanka and Bangladesh they'll almost certainly be through.
BBC SportCopyright: BBC Sport
Post update
On Sky Sports, Nasser Hussain has just called Joe Root "the best England batsman ever in all formats". Big call, but can you really argue?
Post update
Vic Marks
Ex-England spinner on BBC Test Match Special
"This game will have transformed this group. Halfway down England were looking at needing help to qualify but now it is in their own hands. And there are easier games coming up. They will worry about their bowling, but here South Africa's Dale Steyn was given only two overs."
Captain's view
South Africa captain Faf du Plessis: "We've all played this game long enough to know that no score is unchaseable and that was the message to our bowlers. England batted very aggressively in the first six to put us under real pressure. They batted exceptionally well but there were way too many extras from our point of view."
Captain's view
England captain Eoin Morgan: "Honestly I felt we had to play out of our skins and we did just that. There is a lot of talent in our group and the best way for us to play is how we did tonight. The freedom that we play with is the best solution for us. We had a lot of big chases in the last year, and the start we got from Roy and Hales, they were both outstanding."
View from the coaching staff
Post update
Unsurprisingly, that is the highest run chase in the history of the World T20, beating the 208 that South Africa chased down against West Indies in the very first game of the first tournament.
It is the second highest run chase in the history of T20 internationals...
Post update
Vic Marks
Ex-England spinner on BBC Test Match Special
"What a night. For everyone apart from the pace bowlers. It was a nightmare for them. Roy and Hales went hell for leather from the start but then later there was an element of calculation lower in the order from Root and Buttler to keep things ticking over."
Post update
Post update
That really was just brilliant, wasn't it?Joe Root was magnificent: he didn't blast, he didn't heave, he trusted his natural game, timing the ball and brilliantly manufacturing ingenious angles.
But let's reserve some praise for Jason Roy too. Before today he was averaging 13.2 from nine T20 internationals. But he was utterly superb at the start of England's innings, setting a cracking tempo and giving them belief when they had none.
Player reaction
More from England's Joe Root: "We knew we just had to back the natural instincts and play good cricket shots. After the start we got, we couldn't have asked for better, it made the middle order a lot easier and put South Africa under pressure straight away, which is exactly where we needed to be.
"There were 460 runs or whatever, it's a tremendous wicket. I'm sure the batters will want to wrap it up and take it with them all tournament."
Post update
Once, just once, I'd like to see a player in a post-match interview say, "Yeah, obviously I played like an absolute god, it was brilliant." But they never do...
Player reaction
England's Joe Root: "It’s just nice to contribute to a winning team. When they got such a big score at halftime all we we spoke about was not getting greedy and trying for 20 an over. We knew we had to build some partnerships to take it deep. We were calm under pressure, and this sets up nicely for the rest of the tournament."
"That has to be one of the most dramatic victories in the history of the game. Absolutely taken apart in the field, England responded brilliantly, masterminded by Joe Root."
Post update
Vic Marks
Ex-England spinner on BBC Test Match Special
"This will be such a fillip for England, and a hammer blow for South Africa. Root marshaled England, Roy alongside Hales was fantastic at the start, getting the target down to something manageable. They've gotten out of jail, but have done it with such style."
ENGLAND WIN BY TWO WICKETS
They've done it! Absolutely incredible, incredible. Moeen somehow blasts Kyle Abbott over the top and England go through for the winning run.
What a sensational victory. Everything that could go wrong in the field did, they were on the end of an absolute hammering and somehow they've turned it around. What a way to break a sequence of six losses in limited-overs internationals.
Post update
Vic Marks
Ex-England spinner on BBC Test Match Special
"You said it would be a nice easy task.. Two wickets have fallen in this over! If we have a super over here, I don't fancy England's chances... Surely they cannot muck this up?"
Live Reporting
James Gheerbrant
All times stated are UK
Get involved
BBC SportCopyright: BBC Sport 
Latest PostGoodbye
Right, that's it from us after an extraordinary day's cricket. We thought we'd been treated to a thriller when New Zealand scraped past Australia, but that really was something else from England.
Join us tomorrow for the not exactly small matter of India-Pakistan tomorrow afternoon. Until then, goodbye.
Get Involved
#bbccricket
Post update
Vic Marks is absolutely right about the effect on the group table. England would have been out of it if they've lost, but now they're in with a real chance - if they beat Sri Lanka and Bangladesh they'll almost certainly be through.
Post update
On Sky Sports, Nasser Hussain has just called Joe Root "the best England batsman ever in all formats". Big call, but can you really argue?
Post update
Vic Marks
Ex-England spinner on BBC Test Match Special
"This game will have transformed this group. Halfway down England were looking at needing help to qualify but now it is in their own hands. And there are easier games coming up. They will worry about their bowling, but here South Africa's Dale Steyn was given only two overs."
Captain's view
South Africa captain Faf du Plessis: "We've all played this game long enough to know that no score is unchaseable and that was the message to our bowlers. England batted very aggressively in the first six to put us under real pressure. They batted exceptionally well but there were way too many extras from our point of view."
Captain's view
England captain Eoin Morgan: "Honestly I felt we had to play out of our skins and we did just that. There is a lot of talent in our group and the best way for us to play is how we did tonight. The freedom that we play with is the best solution for us. We had a lot of big chases in the last year, and the start we got from Roy and Hales, they were both outstanding."
View from the coaching staff
Post update
Unsurprisingly, that is the highest run chase in the history of the World T20, beating the 208 that South Africa chased down against West Indies in the very first game of the first tournament.
It is the second highest run chase in the history of T20 internationals...
Post update
Vic Marks
Ex-England spinner on BBC Test Match Special
"What a night. For everyone apart from the pace bowlers. It was a nightmare for them. Roy and Hales went hell for leather from the start but then later there was an element of calculation lower in the order from Root and Buttler to keep things ticking over."
Post update
Post update
That really was just brilliant, wasn't it?Joe Root was magnificent: he didn't blast, he didn't heave, he trusted his natural game, timing the ball and brilliantly manufacturing ingenious angles.
But let's reserve some praise for Jason Roy too. Before today he was averaging 13.2 from nine T20 internationals. But he was utterly superb at the start of England's innings, setting a cracking tempo and giving them belief when they had none.
Player reaction
More from England's Joe Root: "We knew we just had to back the natural instincts and play good cricket shots. After the start we got, we couldn't have asked for better, it made the middle order a lot easier and put South Africa under pressure straight away, which is exactly where we needed to be.
"There were 460 runs or whatever, it's a tremendous wicket. I'm sure the batters will want to wrap it up and take it with them all tournament."
Post update
Once, just once, I'd like to see a player in a post-match interview say, "Yeah, obviously I played like an absolute god, it was brilliant." But they never do...
Player reaction
England's Joe Root: "It’s just nice to contribute to a winning team. When they got such a big score at halftime all we we spoke about was not getting greedy and trying for 20 an over. We knew we had to build some partnerships to take it deep. We were calm under pressure, and this sets up nicely for the rest of the tournament."
Praise from Brian Charles Lara
Post update
Jonathan Agnew
BBC Test Match Special
"That has to be one of the most dramatic victories in the history of the game. Absolutely taken apart in the field, England responded brilliantly, masterminded by Joe Root."
Post update
Vic Marks
Ex-England spinner on BBC Test Match Special
"This will be such a fillip for England, and a hammer blow for South Africa. Root marshaled England, Roy alongside Hales was fantastic at the start, getting the target down to something manageable. They've gotten out of jail, but have done it with such style."
ENGLAND WIN BY TWO WICKETS
They've done it! Absolutely incredible, incredible. Moeen somehow blasts Kyle Abbott over the top and England go through for the winning run.
What a sensational victory. Everything that could go wrong in the field did, they were on the end of an absolute hammering and somehow they've turned it around. What a way to break a sequence of six losses in limited-overs internationals.
Post update
Vic Marks
Ex-England spinner on BBC Test Match Special
"You said it would be a nice easy task.. Two wickets have fallen in this over! If we have a super over here, I don't fancy England's chances... Surely they cannot muck this up?"