The home side, playing at Bynea RFC, got off to a fantastic start as winger Josh Adams crossed the whitewash after just two minutes following a charge-down.
Second row Alex Washbourne added a second try at the ten minute mark with outside half Dan Jones converting.
RGC1404 showed great steely determination to hit back with a try just minutes later before adding a second at the 25 minute mark.
The Scarlets side were keen to play an expansive game working through the phases. Despite a few opportunities going amiss due to a lack of concentration the players pulled together to show great determination and skill.
A further four tries were scored by the home side in the second including two tries for winger Josh Adams in the final ten minutes to make it a hat-trick and sealed the victory for the Scarlets.
Final score Scarlets 39 RGC1404 17