Thomas "Tommy Gun" Oosthuizen easily outpointed Aaron Pryor jnr, whose fighting father was known as the Hawk, to keep his IBO super-middleweight title in Biloxi, Mississippi, on Saturday night.
Oosthuizen dropped Pryor in the third round but in the end he had to settle for a unamimous decision.
All three judges scored it 117-111.
Oosthuizen's record improved to 16 wins and one draw, while Pryor dropped to 16-4.
Oosthuizen's father Charles held the SA junior-middleweight and middleweight belts, while Pryor's legendary dad was a world junior-welterweight champion.
Two SA boxers took Pryor's ring name - Welcome Ncita and Masibulela Makepula.