Hashim Amla's resignation is dangerous for England. South Africa will regain the brilliant, consistent Amla the batsman and in A.B. de Villiers they now have a natural leader in charge.
Sport: The week's best plays
From watermelon lovers to monster sixes, these are the most exciting, silly and downright crazy plays in the sporting world this week.
South Africa will be stronger as a result. When you have a captain who is not really enjoying the role or comfortable with it, that can infect the dressing room. But now South Africa have a leader who desperately wants the job and it may prolong de Villiers' Test career. There had been talk of him retiring at the end of the series but who knows, maybe he will play for a couple more years, which will only be good news for Test cricket.
I respect Amla for stepping down now. He could have dragged it out for the rest of the series but he has gone out on a high, having scored a double hundred and saved the team from a defeat that would have ended their chances of winning the series.
He hands over to de Villiers with two Tests to go and South Africa still in with a chance to win 2-1. A new captain can make an instant impact and there is still plenty of life left in this series.
Amla will have been churning over this decision ever since the India tour. I think the final straw came during England's first innings in Cape Town, when the ball travelled the distance and he did not attack. He would have stood at mid-on and thought, 'This is not for me'. He had no Dale Steyn, no Vernon Philander and was having to guide a young bowling attack. He probably realised he did not have the mind for the job. I am sure it is why he looked so much more relaxed when he went out to bat. His mind was made up and he could concentrate on batting.
He appeared agitated at the crease in Durban. But something clicked in Cape Town. He was the Amla of old. He was calm again and looked in control. When your mind is turning over about the captaincy, particularly if you have just taken a battering in the field, it is very hard to watch the ball and react. But he knew he had given up the job and it would have felt like a huge weight off his shoulders.
It shows that captaincy is not for everyone, no matter how good a player you are. It is a difficult job to bat and lead the side and he probably took over South Africa at the toughest time for 20 years, following the retirement of senior players and injuries taking their toll on his bowlers.
England now have a three-day break with their families, which is great but, now more than ever, they will have to switch back on immediately when the series resumes in Johannesburg next Thursday. They are here to play cricket. It can be easy to forget that when you are having fun with the family for a couple of days and there is a danger of not being fully focused by the start of the next match. That could be very costly at the Wanderers against a revitalised South African team.
It was a good week for Test cricket in Cape Town, but it ended with a big warning sign for England. They cannot allow complacency to creep in or to relax during a Test. They were guilty of that on the final day. There was a bit of cloud cover, so the ball did a bit more than on previous days, and South Africa were bowling for victory but England also eased off. Too many batsmen relied on someone else to get the team out of trouble. It was a reminder that they are not the finished article just yet.
I said last week I would like to see them win 10 games on the trot. Well, that has gone but they had enough chances to force a victory. Concentration let them down and they missed too many catches.
England have to be better at lasting five days. If teams come back at them like South Africa did they have to be good enough to counter themselves. They averted disaster on the last day, but the Test ended with South Africa having the upper hand from a position when three days previously I thought that the series was going to turn ugly for them.
At the Wanderers next week the ball might behave like it did here on the last day and England will need to show improved game awareness. In Johannesburg England will face a barrage from four seamers. I played two Tests there. We were hammered in one but won the other. It is key to be able to read game situations and take opportunities when they come along.
There are times when the ball swings. That is when you have to be patient and earn the right to score runs. Then there are other times when the pitch is flat, the sun is out and it is great for batting. That is when you cash in. It is what Marcus Trescothick did in the second innings 11 years ago when he made 180 and we won the game.
It is a great scoring ground and England have an attacking group of players, but it will be about tempo again. They will have to fight through sessions and realise conditions can change in an hour or two, and possibly two or three times a day.
It can swing and seam, so the slip cordon will be in business. England caught well during the Ashes but if you look over a longer period they have been very inconsistent.
It could cost them the game in Johannesburg if they gift lives to South Africa. England will create chances; Stuart Broad and James Anderson are six years older than the last time they played in Johannesburg, when England were well beaten, and will be a real handful on that pitch.
England lost there in 2010 because they took the ball on at the wrong times, and players got out pulling because they could not cope with the extra bounce.
The Telegraph, London