The visitors had come into the game with momentum having beaten both Cavalieri Prato and Perpignan in the Amlin Cup, but despite dominating possession in the opening half they struggled to create any openings.
Replacement Steffan Jones looked to have offered them the consolation of a bonus point with his late penalty but it was to be Stephen Jones' night as he contributed 17 points with the boot including a late shot at goal to add to Rhys Thomas' try.
Gavin Thomas was penalised early on for lying on the wrong side allowing Stephen Jones to slot three points from the left, but the Dragons responded soon after when Jonathan Edwards was penalised for coming in from the side and Jason Tovey duly converted to make it 3-3.
Aled Brew came close to the first try of the evening as he made the most of Martyn Thomas' quick hands only for Gareth Maule to get back and drag him into touch before he crossed the line.
However when Brew came through from the wrong side at a ruck Stephen Jones was able to put the Scarlets back in front.
The veteran Welsh international extended the lead to 9-3 after Thomas was again penalised at the breakdown.
The Dragons deservedly got a penalty back after Edwards strayed off side and Tovey wasted no time slotting it to make it 9-6 with five minutes to go before half-time.
And a stupid block from Ken Owens gave the Dragons the chance to draw level but they instead chose to kick for the corner and go for a try.
However the gamble did not pay off as the Scarlets forced them back before turning the ball over and Stephen Jones' delightful crosskick found new signing Viliame Iongi and after he was stopped short of the line, Rhys Thomas barged over for the opening try. Stephen Jones added the conversion for a 16-6 half-time lead.
Jason Tovey brought the Dragons back to within a score with his third penalty but the Dragons struggled to threaten the Scarlets' tryline.
With 15 minutes remaining the Dragons were penalised for obstruction but Dan Evans missed the resulting penalty from distance.
However after a good break from Adam Warren, Dragons No.8 Tom Brown killed the ball and was sent to the sin bin, Stephen Jones making the score 19-9 with just over ten minutes to go.
Steffan Jones then added the crucial penalty to put the Dragons back to within seven before Stephen Jones added his final kick of the evening with his Dragons counterpart missing a penalty chance in the dying seconds.
|Scarlets Score Card|
|Rhys M. Thomas||1||5|
|Newport Gwent Dragons Score Card|