LLANELLI fly-half Jordan Williams sealed victory for his side with the last kick of the game.
The fly-half landed a penalty from 35 metres to give his side the points against their regional neighbours.
It brought a dramatic end to an enthralling game which neither side deserved to lose.
With 79 minutes gone Llandovery were leading 26-23 and seemingly in control, but a yellow card for No. 8 Kieran Murphy saw two late Williams penalties snatch the spoil
The Drovers had beaten Llanelli 32-22 in a thriller at Church Bank in October and deserved at least to share the spoils in a high-scoring blinder of a contest.
Llanelli team Manager Anthony Buchanan said: "Both sides put on a fine display of adventurous rugby and as a region we should be proud of the way our Premiership clubs are playing. Both sides approached the game the right way and the entertainment was first class."
Llandovery coach Lyndon Lewis was extremely disappointed at the result.
"I don't say we deserved to win but we certainly did not deserve to lose and if we had taken two gilt-edged chances in the second half we would have sneaked it," he said
"So much comes down to a referee's interpretation in key areas of the field that such a dramatic end is always on the cards.
"We are still in with a shout of a play-off spot but need to win our next two games — at home to Cross Keys on Friday and away to Bridgend on March 23 — to keep in touch."
Both halves were fiercely contested with attack, counter-attack, thrills and spills the order of the day.
Llanelli had the boost of an early 7-0 lead when wing Kristian Phillips profited from hesitant tackling to slice through the middle, but the Drovers responded with a penalty from fly-half James Garland before full back Chris Knight slalomed through for a converted try.
From the restart, home wing Kyle Evans snatched the ball in mid air and with Williams adding the conversion and two penalties to just the one from Garland, it was 20-13 to Llanelli at the break.
With home prop Aled Hopkins sin-binned, Llandovery raced into 23-20 lead after a Garland penalty and converted try from Knight following a grand run from centre Jack Roberts.
The fly halves swapped penalties and just after another Llanelli prop — Shaun Hopkins — was yellow-carded, a brilliant Roberts break was only foiled by a cover tackle from Evans on Lee Rees.
Llandovery looked to be hanging on but with No. 8 Murphy sin-binned, Williams tied the scores with a penalty off the upright.
That looked to be that but Llandovery lost their own ball at a scrum, were penalised on the floor and up stepped Williams to put over the vital kick for a personal tally of 19 points.
Llanelli: : Tries: K. Phillips, K. Evans. Cons: J. Williams (2). Pens: J. Williams (5).
Llandovery : Tries: C. Knight (2). Cons: J. Garland (2). Pens: J. Garland (4).
By Huw S Thomas..courtesy of SWEP