Australia vice-captain David Warner claimed that a "vile and disgusting" remark about his wife by South Africa's Quinton de Kock led to their ugly altercation.
Warner said he was used to taking flak from fans and opposition players, but claimed De Kock's remark crossed a line.
"The other day I was probably out of line. I've seen the footage and I regret the way it played out but for me -- it is how I am and I responded emotionally and regretted the way I played out," he said. "But I'll always stick up for my family. I cop it left, right and centre, especially off the field from spectators. I am used to that and it doesn't bother me. But in the proximity of my personal space and behind me, a comment that was vile and disgusting and about my wife and just in general about a lady was quite poor, I felt."
He added: "When it comes to family or racism comments or anything like that, that's just a no-go zone."
Both players have fined for the incident (Warner 75% of his match fee, De Kock 25%).
The 2nd Test between South Africa and Australia begins today. The Aussies lead the 4-match series 1-0.