An assured kicking display from Jonathan Sexton and two second-half tries drove Leinster to a deserved 36-16 win over Brive at the Stade Municipal.
The defending Heineken Cup champions' first win in Pool Six was founded on Sexton's kicking haul of 19 points, with the tries coming from Lions full-back Rob Kearney and young replacement Kevin McLaughlin, who bagged a late double.
England fly-half Andy Goode landed two first-half penalties for Brive, whose best moment came after the hour mark when their South African flanker Gerhard Vosloo scored a converted try.
Leinster top Pool Six at least until Ospreys host Clermont Auvergne tomorrow.
England's preparations for the Autumn International series were potentially dealt a further blow as Maro Itoje was forced to undergo an x-ray after Saracens' European victory over Scarlets on Saturday night.