Llanelli fought back ten minutes later through scrum half Aled Davies to make the scores 10-7. But Ross Jones scored on the stroke of half-time to ensure the home side went in to the break with an eight point lead.
The sides exchanged penalties early in the second half but a try for Llanelli centre Nic Reynolds looked to have swung the game back in the visitors' favour.
However, minutes later, Jones secured the win for the Ravens with his second try, intercepting a wayward pass to sprint in from 55 metres out.
Llanelli started the game in strong fashion and both kickers missed penalties before Ravens fullback Thomas broke the deadlock. Soon afterwards, an attacking lineout five metres from the Llanelli line was driven over the try-line with Marc Thomas emerging with his hands on the ball.
Then with half-time approaching, Owen Williams broke through and found scrum-half Davies who dove between the sticks to get the visitors on to the scoreboard.
The Ravens refused to lie down though and after more defensive hard work in their own 22, Glenn Lewis showed an incredible turn of pace to chase a kick and turnover possession, with the ball then finding Ross Jones to touchdown for his first of the afternoon.
Both kickers exchanged penalties in the ten minutes after half-time and the scoreboard read 18-13 to the Ravens with half an hour remaining.
Several substitutions for both sides disrupted the flow of the game but after some slick backs play from Llanelli, centre Reynolds crossed the line to give the visitors the lead for the first time in the game.
However, as they looked to pull further in front, Jones pounced on a stray pass and sprinted in from within his own half.
A nervy final ten followed for the Ravens as Llanelli came back to within two points but the home side prevailed.