And with a strong and decisive performance by the men up front, tries coming thick and fast in the second half - with the home crowd at heart and soul rugby country treated to a run of attacking rugby as just reward for their continued loyalty and support of their West Wales region.
Double try counts for wingers George North and Andy Fenby - who tops the scoresheet over the past fortnight with a brace of tries in his London Welsh game the previous weekend, were accompanied by tries from Scott Williams, Kieran Murphy and man of the match Liam Williams.
The Scarlets scorecard was added to with three well-struck conversions from Aled Thomas who once again organised competently at outside-half, followed up by two conversions from Wales outside half Rhys Priestland who came on for his 100th Scarlets appearance in the last 20 minutes of the contest.
Coming into this game, the Scarlets last victory against Leinster was once again in a memorable season opener in September 2009 when the region paid tribute to the late, great Ray Gravell by unveiling his statue outside the front of Parc y Scarlets.
The Welsh region knew they had not beaten European champions Leinster in their last seven encounters in all competitions but the Scarlets put the statistics to bed setting a tempo and level of intent for their season with strong performances across the field.
Head Coach Simon Easterby said a 45-20 victory on their home soil was just the start they needed and applauded an "outstanding" performance by his players - adding in the same breath it was just one game with plenty ahead and that now was not the time to get carried away.
Easterby said: "Of course, if someone had said we'd have beaten Leinster with that scoreline beforehand, we'd have taken it with a smile. It's a great start here at Parc y Scarlets and the boys are rightfully pleased and are in really good spirits after that win.
"We said we'd need to blow away some of the cobwebs with our pre-season fixtures and we showed in our performance this weekend that we've done that.
"To a man, our players emptied the tank tonight ; they put their all into that win and it was really positive to see what we'd worked on and learnt from in our pre-season coming right tonight.
"The players have set a great standard but we know that we have to back that up now on the road before we come back home to play the Ospreys for what will be a thrilling encounter here on September 21st."
Easterby said he was encouraged to see a good mix in the Scarlets game with both the result and level of performance across both halves hitting targets.
"There's always something that you can work on and improve but we can be very positive about that start - we were much more clinical and we have set ourselves a good standard to follow now and kept the pressure on them throughout.
"The good work that Mark Jones is doing on skills and our attack showed this evening, the players finished well and the hard work and commitment by our forwards gave them the platform to play.
"Realistically, it's one game and while it is a dream start, we had that last season against Aironi and then we failed to back that up - so the boys have plenty of work to do now against Glasgow and Connacht before we're back home at Parc y Scarlets for the big West derby.
"There's lots to get our teeth into over the next four weeks and this will give us good confidence and we couldn't ask more from the boys in their opening fixture."
New Scarlets Captain Rob McCusker, who led with a superb performance in the back row on Saturday evening, applauded his players for their work rate and approach to the game.
He said: "You could tell as we all arrived before the game, the boys were on fire and wanted this game. We said our target is a top four finish and while we've come close before, it's about actually achieving that now for this group of players and for our supporters.
"This first game has set a standard and if we keep it up we'll be on the right path - there's a great feeling in the camp right now but we know there's plenty more to do ahead of us."
NEXT HOME GAME - Scarlets V Ospreys; Friday 21st September 2012 kick-off 7.05pm. Get your tickets early for the big West Wales derby.