THE Scarlets ended a losing streak against Munster stretching five years and 15 matches with a victory built on defensive grit and scrummaging power.
A late breakaway try from wing Andy Fenby sealed the points in a match played out in appalling conditions at Musgrave Park.
But the platform was firmly laid up front.
The Scarlets won a string of penalties from their scrum, while their line-out, with lock Richard Kelly to the fore, also ran smoothly.
After holding Munster to 3-3 at the break, the conditions deteriorated rapidly in the favour of the Welsh side.
And after fly-half Aled Thomas had kicked them into the lead, Fenby pounced on an error by Munster full-back Felix Jones to seal a first victory against the Irish province since the Stradey Park Heineken Cup quarter-final in 2007.
"It was a fantastic result in those conditions," said head coach Simon Easterby.
"I couldn't have asked more than that from the boys, to come out here and dig in for the win.
"The attitude was outstanding and to keep them out late in the first half when we were on our line probably won us the game.
"The conditions were horrible out there, but we took our chances in the second half.
"I would certainly have taken that before the game and we can go into next week's match against Ulster with confidence."
The Scarlets had gone into the game in second spot in the league standings, but decimated by international call-ups and injury.
South African prop Jacobie Adriaanse was handed his first start for the region after a couple of impressive appearances off the bench in the LV= Cup, while an injury to Kieran Murphy meant Llanelli RFC's Craig Price was another to get a first run in the league starting line-up.
Munster, too, were without a host of familiar names, but were defending a strong record at Musgrave Park, where they hadn't been beaten since May 2008.
On a blustery night in Cork, the West Walians had to withstand a storming start from the home side.
It took all the Scarlets' defensive determination, led by outstanding hooker Emyr Phillips, to keep their line intact as Munster dominated possession and territory in the opening exchanges.
The Scarlets didn't help themselves with some loose kicking to renowned counter-attackers like Doug Howlett and Jones and it needed some sharp covering work from scrum-half Gareth Davies to deny the Munster full-back as he chased down his own chip ahead.
With virtually their first foray into the home half, the Scarlets earned a penalty on 16 minutes, but the swirling wind took Aled Thomas's 40-metre kick away from the uprights.
Instead it was Munster who took the lead when the league's leading marksman, Ian Keatley, slotted over after the Scarlets had infringed at a ruck on their 22.
The Scarlets, though, were proving durable opponents with the scrum, in particular, holding firm.
And a period of pressure on the home line resulted in Thomas levelling matters on 29 minutes after Munster fell foul of French referee Laurent Cardona at the breakdown.
With the rain starting to teem down, handling was becoming more and more difficult and didn't aid Munster's desire to push the ball wide.
Munster back-rower Niall Ronan was stretchered off five minutes before the interval after receiving a nasty hit from lock Jake Ball at a ruck.
He was replaced by new South African signing CJ Stander, who came within inches of claiming the game's first try on the stroke of half-time.
The Scarlets defence again held firm for ruck after ruck, although it needed the television match official to rule that Stander had failed to reach the whitewash.
With the elements more and more in their favour, the Scarlets sensed a rare victory on Irish soil.
They were awarded a penalty for a scrum offence three minutes after the restart, but Thomas pushed his attempt wide.
Dan Thomas replaced skipper Johnathan Edwards moments later with Munster bringing on experienced Springbok tight-head BJ Botha in an attempt to cure their scrummaging problems.
In a match dominated by defence, Munster full-back Jones was proving the game's chief attacking threat and when he collected a chip ahead to race clear, it needed some desperate work from Price to prevent a home try.
The Scarlets scrum was earning plenty of penalties and it was from a set-piece drive that gave Thomas the chance to put his side into the lead.
The fly-half held his nerve to land the penalty, with the help of the upright, and then the Scarlets pounced for the match-winning try on 68 minutes.
It all came from a Munster mistake inside the Scarlets half. Gareth Maule hacked through, then Jones made a horrible hash of gathering the greasy ball, allowing Andy Fenby to pounce in the corner.
Thomas converted to make it 13-3 and with less than ten minutes remaining, the game appeared safe.
Thomas hit the post with a another penalty from another powerful Scarlets scrum, with Munster salvaging a losing bonus point from a penalty by replacement JJ Hanrahan with the last kick of the match.