England all-rounder Ben Stokes has been fined 15% of his match fee for an altercation with a spectator on day one of the fourth Test in South Africa.
He was also given one demerit point, which will sit on his disciplinary record for 24 months, by the International Cricket Council (ICC).
Stokes, 28, swore at the spectator during an angry exchange after he was dismissed for two in Johannesburg.
He later apologised for his "unprofessional reaction".
Stokes, the England vice-captain, accepted an ICC charge of using an "an audible obscenity during an international match".
Demerit points can ultimately lead to suspensions from international matches, but Stokes' record was clean before this incident.
"The punishment is what we expected," said BBC cricket correspondent Jonathan Agnew. "It is the basic, lowest punishment that could have been given. He was provoked, he did apologise and admitted the offence."
As Stokes made his way towards the dressing room on the first evening, television pictures captured him using expletives in the direction of someone not on the field of play.
At the end of the day, he was seen in the same part of the ground, talking to spectators and signing autographs.
A statement from Stokes, released later on Friday, said he has been subject to "repeated abuse from the crowd".
He added: "I admit 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."
England director of cricket Ashley Giles said the tourists had requested for security and stewarding to be enhanced for the remainder of the match.
In response, The Wanderers released a statement on Saturday saying: "We have again reiterated to the field of play security (and other sensitive areas) to be more proactive in identifying spectators' comments when players are in and around their respective areas.
"England security has agreed to ensure that at any given time at least one of them will be down at the tunnel entrance from the field to closely monitor any comments from the spectators."
Speaking at the close of play on day two of the Test, England all-rounder Chris Woakes said that "emotions do run high" when playing away from home.
"Unfortunately there was abuse hurled from the crowd and Stokes snapped," he added.
"He admitted he was probably in the wrong and we move on.
"Guys put a lot of time and effort into doing their best for England and sometimes it's not ideal getting abuse from the crowd."