Ireland fly-half Jonathan Sexton kicked 16 points as Leinster extended their unbeaten home run with a 26-15 win over the Scarletsat the RDS on Friday.
The Irish side are yet to be beaten at the RDS this season and duly moved up to second in the Magners League table.
Despite showing plenty of enterprise, the away team made too many errors and weren't helped by the form of their stand-off Rhys Priestland who missed three crucial kicks at goal.
And although the Welsh side controlled much of the opening, it was the hosts who scored first through a try from winger Niall Morris, Sexton converting.
The Scarlets responded by putting the ball through the phases, but they struggled to break down a stubborn Leinster defence. Priestland had the chance to reduce the arrears but his penalty attempt drifted wide.
Instead, it was his opposite number that extended the hosts lead with another three points.
After missing a further kick at goal, Priestland finally managed to get his team on the board, but Sexton duly responded with one of his own.
The Leinster fly-half then added three more penalties with 15 minutes of the second half played before a try by prop Rhys Thomas gave the Scarlets hope.
Priestland kicked the conversion but a yellow card to young centre Gareth Maule gave the home side the impetus they needed to finish off the encounter.
In Maule's absence, Isaac Boss scored the decisive try with Sexton once again adding the extras.
However, the Scarlets had the last say when they took advantage of an overlap to send substitute Nic Reynolds over.
Tries: Morris, Boss
Cons: Sexton 2
Pens: Sexton 4
Tries: R. M. Thomas, Reynolds
Yellow card: Maule (Scarlets - 73rd min)
Leinster:15 Isa Nacewa, 14 Niall Morris, 13 Eoin O'Malley, 12 Fergus McFadden, 11 Dave Kearney, 10 Jonathan Sexton, 9 Isaac Boss, 8 Rhys Ruddock, 7 Dominic Ryan, 6 Kevin McLaughlin, 5 Devin Toner, 4 Leo Cullen (c), 3 Stan Wright, 2 Richardt Strauss, 1 Heinke van der Merwe.
Replacements: 16 Jason Harris-Wright, 17 Jack McGrath, 18 Simon Shawe, 19 Nathan Hines, 20 Paul Ryan, 21 Paul O'Donohoe, 22 Ian Madigan, 23 Daniel Riordan.
Scarlets: 15 Dan Newton, 14 George North, 13 Regan King, 12 Gareth Maule (c), 11 Joe Ajuwa, 10 Rhys Priestland, 9 Tavis Knoyle, 8 Ben Morgan, 7 Josh Turnbull, 6 Rob McCusker, 5 Aaron Shingler, 4 Lou Reed, 3 Rhys Thomas, 2 Rhys Lawrence, 1 Rhodri Jones .
Replacements: 16 Kirby Myhill, 17 Peter Edwards, 18 Simon Gardiner, 19 Damian Welch, 20 Johnathan Edwards, 21 Gareth Davies, 22 Daniel Evans, 23 Nick Reynolds.
Venue: RDS, Leinster
Referee: Andy Macpherson (SRU)