Faf du Plessis says Australia's David Warner and Steve Smith would go a long way to restoring their reputations if they win the World Cup as he prepares to face them for the first time since the ball-tampering incident in Cape Town last year.

South Africa will end its dismal campaign against Australia at Old Trafford on Saturday, while its opponent has already sealed its semifinal place with seven wins from its eight games.

Du Plessis believes that ultimately the batsmen will be remembered for runs and not the sandpaper scandal at Newlands - and he promises there will be no sledging.

“I think their records and their performances will speak much louder than one incident,” he said.

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“They have learnt from that and they have made themselves stronger for it. All of us make mistakes. It is about how you learn and how you move forward.”

Warner and Smith have contributed to the team's success with the bat, and Du Plessis says their presence following their suspensions has made all the difference for coach Justin Langer and his team.

“Australia has been boosted by the two guys coming back into their batting line-up and made them a pretty complete team,” Du Plessis said. “There's not many holes in their team now and they've played some really good cricket at this World Cup.”

Victory for Australia would secure a semifinal against New Zealand, while defeat opens the door for India to take over at the top of the table and leave the Australians facing host England in the knockout stages.

Du Plessis says there will be no taunts muttered towards the pair from his side.

“There was certainly no talk about the past or bringing up comments. As I said back then, and I will say it now, I believe we are pretty low-key team when it comes to verbals,” he said.

The match will be the last in One-Day International cricket for retiring Imran Tahir and JP Duminy, but Du Plessis would not be drawn on his own future.

“Right now is not the best time to be making decisions because you are disappointed, I won't say emotional, but you don't want to be in this mode when you are making career decisions,” he said.