Bob Casey enjoyed a happy homecoming as he helped London Irish edge out defending champions and former employers Leinster 12-9 in a bruising Heineken Cup encounter at the RDS.
Replacement Ryan Lamb emerged as the unlikely hero, putting his kicking demons behind him to boot two crucial second-half penalties for Irish, with the match-winning kick coming in the 80th minute.
Leinster will feel aggrieved as this was a match they could and should have won. They were the side that came closest to breaking the try deadlock, but they never built on a strong opening quarter.
Jonathan Sexton's third successful penalty of this defence-dominated clash levelled it with five minutes to go, only for Lamb to brilliantly steal the headlines with a thumping kick from just inside the hosts' half.
England Under-18 head coach John Fletcher insists his young side will be better for the experience after beating Italy in the bronze final to round out their 2015 Rugby Europe U18 Championship campaign in style.