Leading 22-17 with four minutes to go, England No.8 Zach Mercer burst through some poor tackle attempts by the Baby Boks to dot down for the winner and keep alive their hope of successfully defending their title.
Curwin Bosch had a late attempt at a drop-goal, but it was never on as the England defence rushed on the pivot.
South Africa then tried their utmost best to score the winner with a move from deep within their half, but winger Gianni Lombard dropped the ball giving England the scrum.
It was a fitting end to the match as England’s captain Mercer then booted the ball into the stands to book their place in the final.
The Baby Boks, though, will feel they did well to fight back in the encounter, with England basically controlling the match from the first whistle.
Mercer was the man who got the scoreboard rolling at the start as well, scoring England’s first five-pointer in the second minute already.
But he was matched by his opposite number Juanro Augustus, who again dotted down twice for the Junior Boks.
Trailing 17-7 shortly before the break, it was Augustus’s second try that brought the Bokkies back in the encounter – 17-12.
And when lock Ruben van Heerden scored with 25 minutes remaining, it looked like the Baby Boks were going to spring a surprise.
But then Mercer broke their hearts.