Faf du Plessis wants to see South Africa force beleaguered Sri Lanka to "breaking point" early in the two-match Test series.
Struggling Sri Lanka will start the series in Durban on Wednesday without a win in seven Tests, losing all but one during that dismal run.
Captain Dinesh Chandimal was dropped following an emphatic 2-0 defeat to Australia, so Dimuth Karunaratne will skipper his country against the Proteas.
A new selection panel was appointed in November and Sri Lankan cricket has also been rocked by match-fixing allegations, all of which head coach Chandika Hathurusingha said have had an impact in the dressing room.
South Africa captain Du Plessis says his side will show no mercy on the tourists as they eye a whitewash.
"It's important for us to keep them under pressure to make sure they don't start the series well." said the batsman.
"If we can do that, possibly their breaking point will be a little bit sooner than it would [usually] be because of all the stuff that's happening away from the game."
He added: "They have had a tough time in Australia and there have been a lot of things happening away from their team,
"It's not ideal for them but I will always respect the opposition we play against. Our preparation doesn't change."