Carmarthen ..26 Merthyr .......... 13
FRONT-runners Merthyr were brought back down to earth by Carmarthen Quins.
Winger Terri Gee touched down for the Ironmen early on, but the West Walians pulled away with a pair of second-half scores. Scarlets No.8 Morgan Allen crashed over before scrum-half Connor Lloyd sniped in to seal the upset at the Park.
Outside-half Steffan Marshall fired the hosts in-front with two penalties for an early 6-0 lead.
But the Ironmen fought back as Gee glidedin for a converted try.
The visitors were hit hard by the injury of flanker Osian Davies, and found themselves behind again after a third Marshall penalty.
The kickers traded penalties again to make it 12-10 to the Quins at halftime, before Allen barged over for a converted score.
Jarvis landed another three-pointer, but the West Walians wrapped up the victory at the death.
After a spell of heavy pressure, scrum-half Lloyd spotted a gap and darted through to score, with Marshall converting to seal the 26-13 triumph.