With three out of three wins at home in the past month, the home tie against 10th placed Edinburgh will be another vital fixture in the Scarlets hunt for a play-off place.
The Scarlets now sit in fifth on 46 points one point behind four-placed Ospreys with Ulster, Glasgow and Leinster in the top three.
After a challenging second half in Dublin, the Scarlets left the RDS disappointed with a 32-5 loss to the European Champions having put in a strong defensive performance but lacking enough possession to get into their game.
The Scarlets fought hard when they went a man down, with second row George Earle in the sin-bin for foul play in the line-out.
Last season's runners-up in the PRO12 competition, Leinster who are unbeaten at home in the league this season showed what it meant to them to win on home soil and their proved their ability to keep a stranglehold on a key game.
With 21 unanswered points from the home side in the second half, the Scarlets were unable to stop a potent attack from the hosts who broke away in the final quarter.
Andrew Goodman scored a try and two penalties in the first half with Andy Fenby, the Scarlets top try scorer this season crossing the whitewash again to put the Scarlets 11-5 down at half-time with everything to play for.
Head Coach Simon Easterby said: "It's a disappointing result for us given the hard work the boys put in; but our ill-discipline and individual errors cost us heavily and in the second half we didn't help ourselves as we feed them too many opportunities.
"I wasn't happy with how we finished that game to give away two tries when we were at 18-5 and give them the bonus point - that could come back and bite us."
"Our accuracy had really improved in recent weeks so it was frustrating to see ourselves go backwards - but we'll come back stronger and more determined next week and won't be dwelling on this weekend's result too much.
"We'll work hard in the build-up to Friday against Edinburgh; we have to react to this immediately and get back some momentum and finish this block of rugby at the right level."
Easterby said the frustration would be something the Scarlets would put behind them on Monday morning.
"It may have taken the gloss off the last couple of weeks for us but the only way to put that right is to put in a strong performance in front of our home supporters.
"We'll need to resurrect the intensity and accuracy we've shown in recent weeks back into our game.
"We showed we had some good line speed, and were competitive at the breakdown in the first half but ultimately our poor discipline let us down.
"We will be working hard to be more effective with the opportunities we always create with the ball and we're confident we can turn this around in six days to get back to where we need to be.
"We'll take nothing for granted against Edinburgh and need to get points from our next game."
Scarlets v Edinburgh, the race for the top four in the RaboDirect PRO12 continues, Friday 1st March kick off 7.05pm, Parc y Scarlets.