Playing against a light wind in the first half, the South Africans protected the ball very well and almost set up camp in the Irish half, with their strong set piece play forcing the visitors to work very hard on defence. A couple of unforced errors cost the hosts though, but they still managed to score three tries before the break.
Ireland, who beat the SA U18 'A' side by 36-33 last Friday, restored some parity in the second half, but the South Africans showed too much composure and added four more tries to their tally for a second convincing win after they beat France by 43-21 in the opening round of the series.
Under pressure for most of the opening exchanges, Ireland conceded a string of penalties and the SA U18s finally breached the visitors' defence in the 15th minute when Jayden Joubert (lock) drove over.
Nine minutes later, SA hooker Clinton Agu burst away from a strong maul and beat one defender for the second try, while Jayden Brits (scrumhalf) added his name to the score sheet with a try from a quick tap penalty shortly before the break. After missing the first two, Ruben Groenewald added the conversion to give the hosts a 17-0 lead at the break.

Kai Pratt on the charge against Ireland.
That changed to 24-0 straight after the restart when the South Africans pounced on an Irish mistake to send Lamla Mgedezi (wing) over in the left hand corner, with Groenewald adding the extras.
A penalty try for a collapsed scrum against Ireland followed a few minutes later, and at 31-0, the SA U18s were firmly in control, although the visitors started to play with more confidence.
They finally scored their first try after 47 minutes when Ireland captain and prop Harry Goslin burst over, but apart from that, the South Africans' defence was generally strong and when Jadrian Afrikaner (replacement wing) exploited space on the left for their sixth try, the momentum swung back in the hosts' favour.
Ethan Adams had the final say a few minutes before the final whistle when the strong midfielder bulldozed his way over the tryline from short range, with Liyema Nela converting to make it 45-5.
In the first game of the day, the SA U18 'A' team were too strong for Georgia, winning by 57-19, while France beat England by 51-20 in the final encounter. The last round takes place at Paarl Gimnasium on Saturday.
Scorers:
SA U18 45 (17) - Tries: Jayden Joubert, Clinton Agu, Jayden Brits, Lamla Mgedezi, Jadrian Afrikaner, Ethan Adams, Penalty try. Conversions: Ruben Groenewald (2), Liyema Nela (2).
Ireland 5 (0) - Try: Harry Goslin.