Despite earning a sanction for a shove and a vociferous send-off, Kagiso Rabada does not need to tone down his aggression. That's the message from Test captain Faf du Plessis, who is on three demerit points himself after shining the ball with saliva that had also come into contact with a mint during the series against Australia last year, and who has taken a grim view of the ICC's code-of-conduct protocols in the past.

Not only would du Plessis like to see a clearer definition for the artificial substances that are not allowed to come into contact with the ball but he also wants Rabada to stay fierce and fiery and thinks cricket is poorer following his sanction. Rabada will miss the second Test at Trent Bridge after earning the suspension.

"I would never say to KG change the way that you are. It's important that he plays the way that he plays the game. Every guy within cricket needs your natural instinct and personality to come out because that creates the best you," du Plessis said, after South Africa were defeated in his absence at Lord's.

Stand-in captain Dean Elgar revealed that Rabada had said sorry to senior management and felt he had let the team down with his behaviour but du Plessis said he did not expect Rabada to do any more. "I would never expect him to apologise to the team. For me that's showing what you're made of. He is showing that he wants to do desperately well for his country," du Plessis said

He also does not expect Rabada to change the way he approaches the game, saying the isolated incident in which he swore at Ben Stokes was simply a moment of frustration for a bowler who did not have things going his way and was not a personal attack on the batsman involved. In fact, du Plessis believes Stokes is capable of dishing out much of the same medicine and has even given him a nickname to reflect his on-field anger.

"I don't think it was anything to do with Ben. I think it was a little bit of frustration from KG. He didn't have the rhythm that he wanted to and it was just frustration coming through," du Plessis said. "I played with Ben and I can tell you he is just as fiery and that's what makes him so competitive and so skillful. I called him 'The Dragon' in the IPL because he breathes fire when he gets angry. That's important, when you have characters to come through like that. That's what I say about KG. Not for one second must he lose that."

South Africa have lost Rabada for the second Test though and du Plessis, like Elgar, thinks both the team and the fans will miss out. "It's a big disappointment for us not having him. It's a shame. He is a real big part of this team. In big Test series like this you want to see your big Test players compete against each other," he said.

Rabada should be back for the third match at The Kia Oval and du Plessis hopes Rabada will pick up where he left off at Lord's, but perhaps be a little more mindful of saying things a safe distance away from the stump mic.

"When you play Test cricket you are fighting for your country and you are doing everything you can to win a game of cricket. Controlled emotion is really important. For me, it's the most important thing as long as it doesn't take you away from your skill. KG doesn't do that, that was just frustration," du Plessis said. "I know his personality. He is a very relaxed and quiet guy. He hardly ever swears at the batsmen in the times we've played together. That was purely just frustration."