Ireland head coach Richie Murphy admitted that he wasn't sure if their World Rugby U20s Championship match against Fiji would go ahead after the death of one of the player’s fathers.
Greig Oliver, father of Jack and a Munster Rugby coach, died in a paragliding accident in Cape Town. Jack was named in the match-day squad the day before.
On Monday, Murphy and captain Diarmuid Mangan had spoken of the squad’s devastation at the news that two pupils from St Michael's College, where six of the panel had attended, had died in separate incidents in Greece and would wear black armbands against Fiji in their final pool game.
Later that day, the news broke that Greig Oliver had died in a tragic accident.
"I am extremely proud of the lads," Murphy told Irish Rugby.
"[Monday] night we weren’t quite sure what was going to happen and whether we were going to play the game or not."
Jack Oliver was at the Danie Craven Stadium as Ireland won a pulsating clash 47-27 in Stellenbosch.
They qualified top of the pool when England and Australia drew their match.
"I thought the guys came together really well and really fronted up in what was the most incredible circumstances that I've ever experienced in 20 years of coaching.
"I am really proud of the boys. We are in a semi-final so we’ve got a lot of to look forward to."
Hosts South Africa await Ireland in Sunday’s semi-final (3.30pm Irish time) in the Athlone Sports Stadium, Cape Town.
The Junior Boks topped their pool after wins over Georgia and Argentina and a loss to Italy.
The sides met in the 2022 Summer Series when South Africa won 33-24 in Italy.
"We played against Ireland in last year's Summer Series and we know what we are up against, as they have a number of those players back at this tournament," Junior Springboks head coach Bafana Nhleko said.
"They have really done well in winning the Under-20 Six Nations and showed some excellent form so far in this competition.
"They also suffered some adversity in the last couple of days and that will give them a deeper sense of purpose going into each game.
"They are a well-coached side, and their skill set will challenge us in different ways to what our pool opponents had."
Follow a live blog of South Africa v Ireland on RTÉ Sport Online and the RTÉ News app from 3pm on Sunday
