The West Wales outfit finished top of the league in 2012 but lost the Play-off final to Gwent last season, but showed by half-time how rampant their back-line can be, with the home side ahead by three tries to one at the break.
Centre Morgan Griffiths and wing Dai Treharne both crossed the whitewash early on with fly-half Daniel Jones converting before scrum-half Gareth Rees consolidated a captain’s performance with a touchdown of his own.
Gwent had not been outclassed and had moments of their own, but failed to keep the score board ticking over at the same rate as the home side.
Hooker Louis Tovey scored their solitary first half try in a match which promised to be a classic ‘end-to-end’ encounter.
Fly-half Scott Turner ensured a maximum haul for Tovey’s efforts when he slotted over the conversion and more of the same would be necessary if Gwent were to mount a second-half fight back to challenge for the spoils.
But a final penalty from Jones, just prior to both sides returning to their dressing rooms to re-group, meant the Carmarthenenshirer side would come out in the second half with an impressive 15 point lead at 22-7.
Indeed, the visitors ran out with a renewed vigour after half-time and dominated possession in the third quarter.
Turner was able to set his backs free time and time again, only to be kept out by an impressively strong home defence.
And, just as some of that pressure seemed about to tell, Coleg Sir Gar landed a sucker blow breaking out of their own half to put wing Treharne free for his second score in the corner, stretching the home lead to 27-7.
Treharne’s brace meant an eighth bonus point this season for Carmarthen and a job well done if they could hold out in the final quarter – and hold out they did, with a stout defensive display meaning the wing’s score went unanswered, something which particularly impressed front row talisman Bradley Davies.
“The boys are very pleased with our defensive effort out there today,” said the Coleg Sir Gar loosehead prop. “We weren’t sure at half-time if we had built up enough of a lead.
“We know they are a good side and we fully expected them to come back at us in the second half and that’s exactly what they did. But when they threw everything at us, not only did our defence hold out, but we were able to take our own chances as they came to us.
“It’s particularly satisfying to pick up a bonus point and I think we can all be proud of our efforts today.”
The match will be shown this evening on S4C at 11.10pm (NB the planned weekly live webcast of the game did not materialise this afternoon due to technical problems).
