Rotherham Titans were edged out by their quarter-final conquerors of last season in a low-scoring affair played out in awful conditions at Clifton Lane.
The Titans were beaten handsomely by Leinster ‘A’ in the last eight last season, a game that produced more than 80 points and countless tries.
On Saturday, it was a lot closer contest, and one very much for the purist as the Irish side prevailed by four kicks to three.
Ross Byrne kicked Leinster in front on 20 minutes before being sent to the sin-bin for infringing at a maul and Ross Jones kicked the penalty.
But during their time with 14 men, Leinster won two penalties which replacement kicker Steve Crosbie converted to give the visitors a 9-3 lead.
Further infringements presented Jones with a 48-metre penalty before the break which he slotted over to halve the arrears.
Jones’ third penalty of the game levelled matters shortly after the break and from then on it was always going to be a case of who kept their discipline in the deteriorating conditions.
Five minutes from time the match-winning score was set up by the Leinster forwards as they manoeuvred up-field; from the base of a ruck the ball was fed back to Byrne in the pocket who struck a marvellous long-range drop goal to seal the game.
The result will leave Rotherham disappointed but they did come up against a dogged defensive display.
Rotherham Titans: Scanlon, Keating, Hayes, Barker, Wilson, Jones (McKinney 64), Davies (Carter 76); Hislop, Maddison (Preece 40), Tampin (Thiede 51), Holmes, Oram (Salmon 64), Gilmour, Birch, Argyle.
Leinster A: Dardis, Fanning, Farrell, Crosbie, McGrath, Byrne, Rock; Dooley (Burke-Flynn 72), Byrne, Burke-Flynn (Bent 45), Beirne, Thornbury (Molony 45), Timmins, Leavy, Ryan (Murphy 65).
Referee: R Thomas (WRU).