We're out of here for now, though. Amy Lofthouse has made sense of events in Perth and you can read the report here.
Enjoy the rest of your Sunday.
Post update
Tomorrow, Australia will look to get their campaign back on track when they meet Sri Lanka at 07:00 GMT.
After that, India take on Bangladesh at 11:00. Both games are at the Waca.
Post update
Not a bad tournament so far, right? Australia beaten, Thailand impressing, now South Africa surprising England.
Get Involved
#bbccricket
Daniel Potter: Not sure about this new coach, gone downhill badly since Mark Robinson left, 2 openers down to come in at 6 & 7 and put Brunt in ahead of both? Sciver at 3?
Remember, England were thrashed by 10 wickets in their final warm-up game against Sri Lanka. All is not well.
Post update
South Africa are huddling for a team selfie on the outfield. What a moment for them. They will feel right in the hunt for a place in the semi-finals.
Post update
South Africa captain Dane van Niekerk: "England are some of the best players of spin in the world, but we spoke a lot about our planning and it is nice when that comes together.
"It was a team performance today. I was batting very slow and I felt like I let the team down. I tried to take it deep. Mignon, Chloe and Sune were brilliant."
Post update
England captain Heather Knight on TMS: "We fought really hard, started well with the bat but the dot balls in the middle cost us. The bowlers responded brilliantly, but it didn't quite come off for us. A brilliant game of cricket, credit to South Africa, they played well. Quite a tight game, so that will take a lot out of us - we've got to park it and move on quickly as we've got a game in Canberra in a couple of days. There are a lot of teams that can win this World Cup, every team has matchwinners. Not too many panic stations - we know we didn't get enough with the bat."
Post update
All of a sudden, England's game against West Indies next Sunday looks very, very big. Lose that, and they will be as good as out.
Post update
Nicky Shaw
Ex-England all-rounder on BBC Test Match Special
The improvement in South Africa's players in the last few years has been because they've come to Australia and England, played in the WBBL and KSL, and been exposed to a higher standard of cricket.
Post update
Incredible celebrations from the South Africans. All of the players and staff are out there. England are wearing some very glum faces.
Post update
Nicky Shaw
Ex-England all-rounder on BBC Test Match Special
It was England's to win - and four massive sixes by the South African girls has been the difference.
South Africa win by six wickets
SA 127-4
A full toss swung for four!
Mignon du Preez has done it! South Africa beat England for the first time at a T20 World Cup.
Another surprise result. England have very little margin for error from now on.
Post update
Nicky Shaw
Ex-England all-rounder on BBC Test Match Special
She has picked that up and it has gone miles. Fantastic shot. Katherine has missed her execution by a long way.
SA 123-4
Amazing shot from Mignon du Preez! Over long leg for six!
South Africa need one to win.
England are floored.
SA 117-4
Mankad warning. Brunt pulls out of her delivery stride....
Post update
Nicky Shaw
Ex-England all-rounder on BBC Test Match Special
I'm not sure my nerves could take a super over.
SA 117-4
Target 124
Brilliant from Brunt. Full length. Inside edge from Luus. Only a single.
SA 116-4
Target 124
Just a single. Du Preez scampers through. Luus on strike. Eight needed.
Live Reporting
Mark Mitchener and Stephan Shemilt
All times stated are UK
View more on twitterView more on twitter 
Latest PostPost update
We're out of here for now, though. Amy Lofthouse has made sense of events in Perth and you can read the report here.
Enjoy the rest of your Sunday.
Post update
Tomorrow, Australia will look to get their campaign back on track when they meet Sri Lanka at 07:00 GMT.
After that, India take on Bangladesh at 11:00. Both games are at the Waca.
Post update
Not a bad tournament so far, right? Australia beaten, Thailand impressing, now South Africa surprising England.
Get Involved
#bbccricket
Daniel Potter: Not sure about this new coach, gone downhill badly since Mark Robinson left, 2 openers down to come in at 6 & 7 and put Brunt in ahead of both? Sciver at 3?
Post update
Post update
Remember, England were thrashed by 10 wickets in their final warm-up game against Sri Lanka. All is not well.
Post update
South Africa are huddling for a team selfie on the outfield. What a moment for them. They will feel right in the hunt for a place in the semi-finals.
Post update
South Africa captain Dane van Niekerk: "England are some of the best players of spin in the world, but we spoke a lot about our planning and it is nice when that comes together.
"It was a team performance today. I was batting very slow and I felt like I let the team down. I tried to take it deep. Mignon, Chloe and Sune were brilliant."
Post update
England captain Heather Knight on TMS: "We fought really hard, started well with the bat but the dot balls in the middle cost us. The bowlers responded brilliantly, but it didn't quite come off for us. A brilliant game of cricket, credit to South Africa, they played well. Quite a tight game, so that will take a lot out of us - we've got to park it and move on quickly as we've got a game in Canberra in a couple of days. There are a lot of teams that can win this World Cup, every team has matchwinners. Not too many panic stations - we know we didn't get enough with the bat."
Post update
All of a sudden, England's game against West Indies next Sunday looks very, very big. Lose that, and they will be as good as out.
Post update
Nicky Shaw
Ex-England all-rounder on BBC Test Match Special
The improvement in South Africa's players in the last few years has been because they've come to Australia and England, played in the WBBL and KSL, and been exposed to a higher standard of cricket.
Post update
Incredible celebrations from the South Africans. All of the players and staff are out there. England are wearing some very glum faces.
Post update
Nicky Shaw
Ex-England all-rounder on BBC Test Match Special
It was England's to win - and four massive sixes by the South African girls has been the difference.
South Africa win by six wickets
SA 127-4
A full toss swung for four!
Mignon du Preez has done it! South Africa beat England for the first time at a T20 World Cup.
Another surprise result. England have very little margin for error from now on.
Post update
Nicky Shaw
Ex-England all-rounder on BBC Test Match Special
She has picked that up and it has gone miles. Fantastic shot. Katherine has missed her execution by a long way.
SA 123-4
Amazing shot from Mignon du Preez! Over long leg for six!
South Africa need one to win.
England are floored.
SA 117-4
Mankad warning. Brunt pulls out of her delivery stride....
Post update
Nicky Shaw
Ex-England all-rounder on BBC Test Match Special
I'm not sure my nerves could take a super over.
SA 117-4
Target 124
Brilliant from Brunt. Full length. Inside edge from Luus. Only a single.
SA 116-4
Target 124
Just a single. Du Preez scampers through. Luus on strike. Eight needed.