AB de Villiers played down suggestions he may retire from Test cricket after overseeing a crushing defeat to England in his first match since succeeding Hashim Amla as captain.
South Africa dismissed England for 323 on the third morning at the Wanderers, before reaching lunch on 16 without loss - holding a lead of six.
However, Stuart Broad then returned 6-17 as the Proteas dramatically collapsed to 83 all out, enabling England to secure a convincing victory and an unassailable 2-0 series lead ahead of the final Test at Centurion.
De Villiers' future in the five-day game has been the subject of much concern since he revealed concerns over his workload in Durban last month.
However, the 31-year-old said: "I was never thinking of leaving Test cricket at all. I was just looking to find a way to rest a little bit throughout the year.
"Lots of thoughts have been crossing my mind but this [loss] has got absolutely no influence on that.
"Playing on the cricket pitch has never been an issue for me, it's just a matter of keeping myself fresh. I just have to try and find a balance to keep my fight going and keep that skill level up."
Reflecting on a loss that will see South Africa relinquish their position at the top of the ICC Test rankings, De Villiers added: "We just got a good hammering from the opposition, there's no other way to put it.
"It's never nice to lose a series and I almost feels like all hope is gone, but I'm still the kind of guy that will get myself going for that last Test match, and get the team going.
"I believe our form of late has been pretty poor and it'll take something special to turn it around.
"The talent is there, it's just a matter of finding consistency and applying pressure more often."