The Irish province, much changed from their quarter-final victory over Leicester Tigers on April 7, rallied from a 26-14 half-time deficit to maintain their unbeaten streak.

Tries from Vakh Abdaladze, Liam Turner, Michael Milne, Rob Russell, Chris Cosgrave helped the youthful visitors to victory, with debutant Sam Prendergast kicking four conversions and two penalties, including a late winner.

The four-time winners of EPCR’s elite competition, who take on Stade Toulousain in Dublin on April 29, started well, with prop Abdaladze crossing in just the first minute for a converted score.

However, two tries for Emirates Lions, one converted, turned the game on its head, only for centre Turner to restore Leinster’s lead with their second converted try.

Yet another two quickfire tries for the hosts before half-time, though, saw the runaway URC leaders staring down the barrel of a first defeat of the campaign.

Those fears increased, despite a converted score from prop Milne early in the second period, when Emirates Lions kicked a penalty and were awarded a penalty try to leave Leinster trailing by 15.

But the fightback began with fly-half Prendergast kicking the first of two crucial penalties, before replacement Russell and full-back Cosgrave scored a try apiece, with Prendergast adding the extras for the second to level matters and landing the decisive penalty with the clock in the red.

Meanwhile, Leinster’s 2022 Heineken Champions Cup final opponents, Stade Rochelais, also triumphed in domestic action, cruising to a 26-6 home win over Aviron Bayonnais in the TOP 14.

La Rochelle, who defeated Leinster 24-21 in last year’s final and face Exeter Chiefs on April 30 in their semi-final this year, kept the pressure up on league leaders Toulouse with tries from Thomas Berjon and Rémi Picquette plus 16 points from Hugo Reus.

Heineken Champions Cup semi-finalists Leinster Rugby continued their outstanding form this season with a superb fightback to defeat Emirates Lions 39-36 in the United Rugby Championship (URC) on Saturday and register their first ever win in South Africa.