Ben Stokes described his foul-mouthed exchange with a fan during the fourth and final Test as "unprofessional" while maintaining he was a victim of "repeated abuse".
The England vice-captain was walking off the field after being dismissed by Anrich Nortje when he paused in his steps to engage in an angry outburst with a spectator.
Stokes' insults were picked up the broadcasters but weren't telecast live though they were later shown and subsequently distributed widely on social media.
"Come say that to me outside the ground, you f***ing four-eyed c***," the all-rounder appeared to say while on the steps leading to the dressing room.
Witnesses told the Guardian that a middle-aged man donning a South African cricket jersey targeted Stokes by likening him to pop star Ed Sheeran and allegedly calling him a "ginger c***".
"I wish to apologise for my language that was heard on the live broadcast today after my dismissal. I should not have reacted in that way," Stokes said in a public apology shared on Twitter.
"As I was leaving the playing area, I was subjected to repeated abuse from the crowd. I admit that my reaction was unprofessional, and I sincerely apologise for the language I used, especially to the many young fans watching the live telecast around the world.
"Throughout the Tests so far, the support from both sets of fans (England and South Africa) has been brilliant. One incident will not ruin such a competitive series, which we are determined to win."
Stokes could face disciplinary action for using an audible obscenity and could be charged for breaching Article 2.3 of ICC's Code of Conduct, in which case he will cop a single demerit point.
However, if his actions are interpreted as a threat of assault on the spectator, he could even receive a suspension.
Spectators at the Wanderers have a nefarious reputation for being among the most unruly with several unsavoury incidents taking place here in the past.
In light of this ugly spat and other occurrences of the tourists' staff being abused by fans present at the stadium, England men's cricket managing director Ashely Giles asked for more security personnel patrolling the fences.
Giles revealed that members of the England support staff had also been subjected to offensive words from the crowd and called the whole episode "disappointing".
"It is disappointing that a member of the public has gone out of their way to abuse Ben as he was leaving the field. Ben is fully aware that he should not have reacted in the way that he did and apologises for his actions.
"In addition to this incident, members of our support staff were subjected to personal abuse during and after the day's play.
"We have requested the venue to ensure that security and stewarding are enhanced for the remainder of the match so that players and staff members can go about their duties without provocation," he said.