Cape Town - Proteas captain Faf du Plessis says the difference between his side and England has been the ability to score "big runs".
The Proteas lost the third Test in Port Elizabeth by an innings and 53 runs on Monday to go 2-1 down in the series with only the fourth Test in Johannesburg to come.
That match starts on Friday, but South Africa's misfiring top order suggests that there will be changes for the hosts with Temba Bavuma in line to regain his place in the starting XI at the expense of Zubayr Hamza.
There have been three centuries so far in the series with all of them belonging to England, and that is where Du Plessis believes his side has fallen short of their opposition.
"We made real strides in that first week and that first Test match where I felt like we had turned a corner," the skipper said.
"The last two Test matches, obviously fighting in the second one, but we feel like we have taken a step back in the third Test especially from a batting point of view.
"Yes, there was spin, but nothing that should get us out for that kind of total.
"England are just showing us from a batting point of view how to get yourself in, apply yourself and get big runs. I think that's the only difference at the moment."
Spin was responsible for 10 of the 20 South African wickets to fall at St George's Park.
Du Plessis also made special mention of the ICC's 2019 Cricketer of the Year and England's Ashes and World Cup hero, Ben Stokes.
"Ben Stokes is a player that it very good and we're struggling to get him out," said Du Plessis.
"He's consistently scoring big runs where in our team, if somebody gets in, he gets out. As soon as a partnership is developing, the partnership stops. They had one partnership of 200, and once that happens you get in front of the game.
"You have to absorb pressure, and we're not doing that as well as we should as a batting unit."
Stokes is the leading run scorer in the series so far and has posted knocks of 47, 72 and 120 in the last two Tests.
Du Plessis acknowledged that his form, and that of the entire top order, had not been good enough.
"Confidence is a big thing in our batting line-up. We need to get confidence back and time in the middle and runs on the board. There is no doubt in my mind that it will come eventually," he said.
"There are quite a few of us in the same boat."