SCARLETS won (13-6) for the first time in eight visits to Musgrave Park as they outmuscled Munster in horrendous conditions.
A penalty apiece from Ian Keatley and Aled Thomas were the only scores of a first half which saw Niall Ronan carried off on his comeback.
Thomas kicked Scarlets ahead in the 68th minute and Munster handed them a soft try shortly afterwards.
The Welshmen launched a kick chase after Luke O'Dea had lost possession, the retreating Felix Jones getting two bites at the loose ball before seeing it squirt free over the line for Andy Fenby to ground it.
Thomas' successful conversion sealed Scarlets' first victory over Munster in 16 meetings.
The hosts earned a late bonus point, though, as JJ Hanrahan split the posts with the final kick.