Ireland will face host nation South Africa in the World Rugby U-20 Championship semi-final in Cape Town this weekend.Richie Murphy's team booked their place in the last four on Tuesday, putting a desperately difficult 48 hours behind them to defeat Fiji 47-27 in Stellenbosch.On Monday Greig Oliver, the Munster elite performance officer and father of Ireland U20 out-half Jack, died in a paragliding accident.That came after the sudden passing of teenagers Andrew O'Donnell and Max Wall on holidays in Greece at the weekend; the pair were known to several members of the Ireland team at St Michael's College in Dublin.England will meet top seeds France in the other semi-final.Ireland and the Junior Boks collide at Cape Town’s Athlone Sports Stadium on Sunday [3.30pm ko Irish time].Having claimed their second successive U-20 Six Nations Grand Slam in the spring, Murphy’s charges are now unbeaten in 10 matches stretching back a year to the U-20 Six Nations Summer Series in Italy.South Africa were the last team to beat them, winning 33-24 last June in Verona.