Leinster made it two narrow wins out of two in Pool Five of the 2012/13 Heineken Cup after defeating the Scarlets 20-13 in Llanelli on Saturday.
The champions started like a train at the Parc y Scarlets and quickly built up a commanding lead inside the opening quarter of an hour of the game.
Leinster got on the scoreboard inside the first two minutes via the right boot of Jonny Sexton and it wasn't long before that same weapon provided the opening try of the match. The Irish fly-half delivered an inch-perfect cross-field kick from right to left after a good attacking lineout was won and Isa Nacewa accomplished the impressive feat of leaping to claim the ball above wing George North and wrestling to touch it down.
Leinster were dominant at the breakdown, pilfering ball left, right and centre and taking advantage of their opponents' errors and ill-discipline, but they had to settle for just another Sexton penalty before the break to leave the score 11-0.
After Sexton and Rhys Priestland had exchanged penalties early in the second half, Gareth Maule finally got the Scarlets back into the game with an outstanding individual try, outpacing Brian O'Driscoll to score in the right-hand corner.
Two further Sexton penalties stretched the visitors' lead to ten again but, after Ian Madigan took his opposite number out in the air to leave the Irishmen with 14 men for most of the final ten minutes, Priestland slotted over the penalty to get the Scarlets back within range.
That was as close as they got though. Even with the extra man, they were unable to seriously threaten the Leinster line they only just managed to hang onto the bonus point as Sexton sent a late penalty attempt wide of the posts.
Pen: Priestland 2
Pen: Sexton 4
Scarlets: 15 Liam Williams, 14 George North, 13 Gareth Maule, 12 Scott Williams, 11 Andrew Fenby, 10 Rhys Priestland, 9 Tavis Knoyle, 8 Rob McCusker, 7 Josh Turnbull, 6 Aaron Shingler, 5 Johan Snyman, 4 George Earle, 3 Samson Lee, 2 Matthew Rees, 1 Phil John.
Replacements: 16 Ken Owens, 17 Shaun Hopkins, 18 Deacon Manu, 19 Tomas Vallejos, 20 Jon Edwards, 21 Gareth Davies, 22 Aled Thomas, 23 Morgan Stoddart.
Leinster: 15 Ian Madigan, 14 Fergus McFadden, 13 Brian O'Driscoll, 12 Gordon D'Arcy, 11 Isa Nacewa, 10 Jonathan Sexton, 9 Eoin Reddan, 8 Jamie Heaslip, 7 Shane Jennings, 6 Kevin McLaughlin, 5 Damian Browne, 4 Leo Cullen (c), 3 Mike Ross, 2 Sean Cronin, 1 Cian Healy.
Replacements: 16 Richardt Strauss, 17 Heinke van der Merwe, 18 Jamie Hagan, 19 Devin Toner, 20 Jordi Murphy, 21 Isaac Boss, 22 Andrew Conway, 23 Fionn Carr.
Referee: Greg Garner