Pembroke completed the double over old rivals Llangwm at Pill Parks and in doing so secured the Palmer Cup, which is competed for annually between the two sides.
The Scarlets had won the first leg at Crickmarren by a massive 86-3 but there was no chance of a similar margin here as the Wasps, superbly led by Ian Griffiths, were only 13-3 adrift at the break and never let the opposition take total control up front.
Griffiths was joined by Roy Venables, Ashley Jack, Aled Morgan and the rest of the Wasps’ pack in setting up early possession for them to score first when full back Lewis Murphy landed a penalty.
Pembroke had young fly half Rhys Johns responding with an equalising penalty before the Scarlets grabbed the games’ first try when Barry Bowen broke from his centre berth to round off some quick hands.
Johns converted and added a second penalty to put the Scarlets ten points ahead at half time.
The second half was equally as hard-fought as Pembroke had the bulk of possession but made lots of handling errors as Gareth Jones, Will Edwards, Jordan Gwilliam and Dan Manning caught the eye with some powerful surges.
It was Jones who increased the Scarlets’ lead soon after the interval as he powered over from a lineout take and drive. Centre Bowen then claimed his second try midway through the half as he rounded off a 50-metre move with some style.
But neither side was able to add further points and Llangwm finished on the attack after a few moments of farce when the Scarlets conceded four lots of ten metres after debating a decision by referee Emyr Thomas. Even after the ensuing penalty looked to have failed to find touch properly the Wasps had another penalty awarded, but the Scarlets’ defence held firm.
Llangwm: Lewis Murphy, Mark Brimacombe, Josh Davies, Adam James, Henry Brant, Chris Thomas, Jonathan Brock, Aled Morgan, Mike Terry, Roy Venables, Ryan John, Lewis Holder, Gareth Jones, Ian Griffiths (capt), Ashley Jack.
Replacements: James Lewis; Dan Morgan.
Pembroke: John Williams, Geraint Jackson (capt), Barry Bowen, Dom Colman, Mark Jones, Rhys Johns, James Skeels, Shamus Wiseman, Gareth Jones, Adam Blunsden, Scott Powell, Will Edwards, Steve Dyde, Dan Manning, Jordan Gwilliam.
Replacements: Simon Cole, Darren Gilbert, Sean Beynon, Richard Murray.