Rob Kearney and Ian Madigan scored two tries apiece as Leinster hammered the Scarlets 42-12 at the RDS.
Rob Kearney and Ian Madigan touched down twice as Leinster recorded their first victory of the Pro12 with a 42-12 triumph over Scarlets
Kearney (twice) and Madigan went over in the first half as the Irish province went into the interval 21-5 ahead.
The Welsh side's response in the opening 40 came through Scott Williams' try, but the defending champions were simply too good as Madigan, Dominic Ryan and Tadhg Furlong crossed the whitewash in the second period to complete the win.
Scarlets had the last say through Johan Snyman but it proved to be mere consolation.
Having won the competition in 2013 and 2014, the hosts didn't get their campaign off to the best of starts by narrowly going down to Glasgow Warriors in round one.
They also found themselves under pressure early on here as Wayne Pivac's men, who drew 32-32 with Ulster last week, opened the brighter, but Rhys Priestland's penalty went wide of the uprights.
That was to prove costly as the hosts went on the attack and Brendan Macken, playing in Brian O'Driscoll's position following the great centre's retirement, fed Kearney to score.
To their credit, the Welsh region were unperturbed and a mistake in midfield from the home side allowed Williams to kick through and touch down.
But Leinster seemed to have the control and were continuously turning over the Scarlets in midfield.
That allowed Matt O'Connor's side to build phases in the opposition 22 and it was no surprise to see Kearney go over for his second try.
Madigan then crossed the whitewash and converted for the third time in the game to give the Irish province a deserved 21-5 lead at the break.
Matters went from bad to worse for the Scarlets in the second half when Phil John was sin-binned and the hosts unsurprisingly took advantage.
Once again, it was their inside centre who carved through the opposition rearguard to go over for the bonus-point and increase the Irish side's lead.
That wasn't the end of the scoring as Ryan and Furlong touched down to complete the visitors' misery, although the Scarlets did get a consolation through Snyman.
Tries: Kearney 2, Madigan 2, Ryan, Furlong
Conversions: Madigan 6
Yellow Card: Heaslip
Tries: S Williams, Snyman
Yellow Card: John
Leinster: 15 Rob Kearney, 14 Zane Kirchner, 13 Brendan Macken, 12 Ian Madigan, 11 Darragh Fanning, 10 Jimmy Gopperth, 9 Isaac Boss, 8 Jamie Heaslip, 7 Shane Jennings, 6 Dominic Ryan, 5 Mike McCarthy, 4 Devin Toner, 3 Mike Ross, 2 Sean Cronin, 1 Jack McGrath
Replacements: 16 Bryan Byrne, 17 Cian Healy, 18 Tadhg Furlong, 19 Ben Marshall, 20 Kevin McLaughlin, 21 Eoin Reddan, 22 Steve Crosbie, 23 Mick McGrath
Scarlets: 15 Liam Williams, 14 Harry Robinson, 13 Gareth Owen, 12 Scott Williams, 11 Jordan Williams, 10 Rhys Priestland, 9 Rhodri Williams, 8 Rory Pitman, 7 John Barclay, 6 Aaron Shingler, 5 Johan Snyman, 4 Jake Ball, 3 Rhodri Jones, 2 Ken Owens (c), 1 Phil John
Replacements: 16 Emyr Phillips, 17 Rob Evans, 18 Peter Edwards, 19 Richard Kelly, 20 Rob McCusker, 21 Aled Davies, 22 Steven Shingler, 23 Adam Warren
Referee: Marius Mitrea (Italy)
Assistant Referees: Mark Patton (Ireland), Jonathan Peak (Ireland)
TMO: Alan Rogan (Ireland)