A try from Ireland scrum-half Guy Easterby try was not enough to prevent high-flying Leinster slipping to a 41-33 defeat to Edinburgh at Murrayfield.
Easterby came off the bench to help Ireland complete a comprehensive 40-13 victory over Scotland at the same venue in the RBS 6 Nations clash on February 12, but the 33-year-old did not have such an enjoyable evening on Saturday.
He handed Leinster a lifeline on the stroke of half-time when he punished dozy Edinburgh defending to nip in under the posts to give David Holwell an easy conversion.
And the Gunners were further stunned on the restart when the Irish again breached their line. This time David Blaney pinched possession and Christian Warner outpaced the home defence to touchdown Holwell's chip kick.
The stand-off's conversion reduced the leeway to just five points to have Edinburgh reeling.
But, just when they looked like caving in, the Gunners found another gear and stretched clear of their Irish opponents to complete a narrow victory.
After losing their Under-20s Six Nations crown to England Under-20s in a thrilling final round, France Under-20s lock Tristan Labouteley insists his side will be out for revenge at this year's Junior World Championship.