The Quins, who are celebrating their 150th anniversary this season, put in a mighty performance and looked set for an extra bonus point until two late tries from the Blue & Blacks enabled them to save some face.
A first defeat of the campaign for Dan Fish’ side meant they dropped to third, while Carmarthen’s second home win of the season moved them up to 11 points and into the mix for the top spot.
Always ahead in the game, Tom Phillips’ home side took the lead in the 14th minute when 21-year-old hooker Lewis Morgan powered over for his fifth try of the season. He had already bagged two tries in each of the opening two games against Swansea and Aberavon.
Almost 21 years on from his debut for the club, the 39-year-old Aled Thomas returned to go through 600 points in his 96th appearance as he notched 11 points on his latest rebirth.
Having left Aberavon in the summer, the former Wales Sevens World Cup winner outside half has been brought in by director of rugby Steff Thomas to add experience to a side that had an average age of 23 in the opening two matches. The aim is for his to help teenagers like fellow No 10 Elis Price to learn the ropes.
Having converted Morgan’s opening try Thomas added a penalty and also supplied the extras to a try by prop James Newnian. It was 24-0 on the half-hour mark when scrum-half Rhodri Davies scored after good work from Scarlets’ flanker Ben Williams in the build-up, with Thomas again converting.
The visitors finally opened their account just before the interval when they spread the ball wide for Wales U20 full back Matty Young to score his first try in Cardiff colours. Osian Darwin-Lewis converted to make it 24-7 at the break.
It took some heroic last-ditch defence from the Quins at times to keep Cardiff at bay and twice the visitors were held up over the line. As the pressure mounted, referee Matthew Leon dished out five second half yellow cards, leaving Carmarthen with only 13 men by the end.
Home skipper Phillips was the first to go to the sin-bin before Cardiff prop Rhys Barrett followed him. Then visiting back row man Aled Ward saw yellow before Iori Badham and Sion Jones ended up on the naughty step in the closing minutes.
Scarlets academy wing Badham botched the bonus-point try for the Quins, which Thomas once again improved, to stretch the lead to 31-7, but those two late Cardiff tries considerably cut the gap as Young grabbed his second and Joe Williams scored.
It was the first win over Cardiff by Carmarthen since January 2022 and they will get the chance to secure the double when they visit the Arms Park in Round 4.
Scorers: Carmarthen Quins; Tries: L Morgan, J Neunian, R Davies, I Badham; Cons: A Thomas 4; Pen: A Thomas. Cardiff: Tries: M Young 2, J Williams; Cons: O Darwin-Lewis, J Williams
