The South Africans scored nine tries, after Scotland took an early lead with a break-away try after just ten minutes.
The Junior Springboks stayed calm and soon reaped rewards for their efforts as first Pierre Schoeman (prop) and then Sergeal Petersen (left wing) crossed the try-line.
Both tries came from a call by captain Handré Pollard, to execute attacking set-plays rather than kicking for poles.
The skipper, who had a superb match, kicked both conversions to give his side a 14-5 lead at the break.
Scotland did well to frustrate the South Africans at the breakdown in the opening stanza, which prevented the Junior Springboks from unleashing their powerful backs.
However, the South Africans got into their full stride after the break and combined their physical presence with skillful play to score seven more tries.
The young South Africans enjoyed much better control of the forward exchanges after the break and this allowed their dangerous backs to strike with purpose.
Pollard started the spark with a great chip and chase that resulted in big winger Greeff scoring. More probing play by the flyhalf saw Jesse Kriel (outside centre) crossing the line to score the bonus-point try.
Not to be outdone by the backs, the forwards played their part and kept to their plays and structure. Lively hooker Malcolm Marx scored after good interplay among the front row and Aidon Davis (no 8) also got on the score sheet, but not before fullback Gelant showed great pace down the blindside for his first JWC try.
A bunch of replacements did not stop the Junior Boks’ momentum and both Kriel and Greeff scored their second tries of the evening to cap off a great performance by the team.
Scorers: South Africa 61 (14). Tries: Pierre Schoeman, Jessie Kriel (2), Lloyd Greeff (2), Malcolm Marx, Sergeal Petersen, Warrick Gelant, Aidon Davis. Conversions: Handré Pollard (7), Jean-Luc du Plessis.
Scotland 5 (5). Try: Jamie Farndale.