Kyle Abbott admitted he finds it tough operating in a back-up role for South Africa.
The Proteas rested first-choice bowlers Dale Steyn, Kagiso Rabada and Imran Tahir for Sunday's fourth one-day international against Australia having already wrapped up the five-match series.
Abbott was one of the beneficiaries of the reshuffle and he grasped his opportunity by claiming figures of 4-40 from eight overs, including the scalps of Aaron Finch and David Warner, as Australia were skittled for 167.
South Africa went on to clinch a comfortable six-wicket win and the fast bowler admitted it is difficult to deal with the nature of his role in the squad.
Abbott said: "It's tough not knowing when you are going to get a game. The key is to still tick the boxes at practice and when those opportunities come.
"Coming up against a quality batting line-up like Australia, you need to stay on top of your game even if you are not playing."
Victory for the Proteas at Newlands on Wednesday would secure an unprecedented whitewash over Australia, who have never been on the receiving end of a clean sweep in a five-match ODI series.
"We can't even begin to think what it might be like on Wednesday if it does happen. It has been phenomenal," said Abbott.
"We celebrated well on Wednesday after winning the series and that was the big challenge, to put in another performance knowing that the series was secured and not take our foot of the gas. We did that pretty well.
"Coming up to Wednesday, I don't think we will do anything differently. We will stick to what we've done that's won us four games and hopefully make it five and make some history."
Tabraiz Shamsi took three wickets for South Africa amid a run-in with Matthew Wade that prompted Faf du Plessis to call for the umpires to intervene.
The pair have been charged with breaking the ICC Code of Conduct and will discover the repercussions for their confrontation on Monday, but Wade insisted there was nothing malicious in it.
He said: "It's just competitive cricket. International cricket is hard work. We had a crack the other night and they came back at us today, so it's fair.
"I suppose it can get blown out of proportion at times, with all the technology around now. There are stump mics and cameras everywhere. I enjoy that sort of a game, it got me in the contest straight away.
"We've got to find a way to keep him [Shamsi] out of the contest. I think if he doesn't get in the contest with wickets as quick as he did, I think we can keep him a little quieter.