Scarlets kept their top six hopes alive with an impressive win over play-off chasing Leinster, 23-13 in the Pro12.
Steven Shingler's penalty gave the Welsh region a 3-0 lead but Ben Te'o's try and Jimmy Gopperth's three-pointer opened up a 10-3 buffer for the Irish province.
However, tries from John Barclay and Jordan Williams moved the hosts ahead early in the second period. Gopperth reduced the deficit for Leinster, but Rory Pitman's touchdown and Rhys Priestland's effort off the tee sealed a crucial win for the Llanelli-based club.
The home team needed a win to aid their top-six prospects and they started in ideal fashion, pressing the visiting defence.
Wayne Pivac's men were rewarded for that endeavour as Shingler was on target from the tee to take them 3-0 ahead. Scarlets enjoyed over 60 percent possession in the early exchanges but the defence from the Irish province remained strong.
And when they finally got their hands on the ball, the Dublin-based outfit proved clinical. Leinster went through the phases on the opposition 22 before Te'o's nice line scythed through the hosts' rearguard for a well-constructed try.
Gopperth then kicked a penalty to extend their advantage, but the Welsh region continued with their high tempo game and it paid dividends as Barclay crossed in the right-hand corner to reduce the arrears at the interval.
The second period started in the same fashion as the first with the home team on the front foot but, unlike in the opening half, they managed to create a try for Williams.
Leinster's fly-half was on target for the third time off the tee to bring the visitors to within two points, but Pitman's touchdown kept the away side at arm's length.
Matt O'Connor's men attempted to get back into the contest and, although they created opportunities, the hosts' defence held firm and Priestland's three-pointer completed the victory.
Tries: Barclay, J Williams, Pitman
Pens: Shingler, Priestland
Pens: Gopperth 2
Scarlets: 15 Jordan Williams, 14 Harry Robinson, 13 Regan King, 12 Scott Williams, 11 Hadleigh Parkes, 10 Steven Shingler, 9 Aled Davies, 8 John Barclay, 7 James Davies, 6 Lewis Rawlins, 5 Johan Snyman, 4 George Earle, 3 Peter Edwards, 2 Ken Owens (c), 1 Phil John.
Replacements: 16 Ryan Elias, 17 Wyn Jones, 18 Jacobie Adriaanse, 19 Jack Payne, 20 Rory Pitman, 21 Gareth Davies, 22 Rhys Priestland, 23 Adam Warren
Leinster: 15 Zane Kirchner, 14 Fergus McFadden, 13 Ben Te'o, 12 Gordon D'Arcy, 11 Luke Fitzgerald, 10 Jimmy Gopperth, 9 Eoin Reddan, 8 Jack Conan, 7 Dominic Ryan, 6 Rhys Ruddock (c), 5 Kane Douglas, 4 Mike McCarthy, 3 Marty Moore, 2 Sean Cronin, 1 Cian Healy.
Replacements: 16 Richardt Strauss, 17 Michael Bent, 18 Tadhg Furlong, 19 Tom Denton, 20 Josh van der Flier 21 Isaac Boss, 22 Noel Reid, 23 Dave Kearney
Venue: Parc y Scarlets
Referee: George Clancy
Assistant referees: Gwyn Morris, Chris Williams
TMO: Tim Hayes