And their lead was extended 2 minutes later after Andy Fenby dived on a loose ball over the line after it escaped the grasp of Felix Jones on two attempts in atrocious conditions. Thomas added the conversion to give Scarlets a ten point cushion.
Rob Penney credited a young JJ Hanrahan for slotting the last minute penalty chance in horrendous conditions to give Munster a vital losing bonus point.
Final score Munster 6 Scarlets 13.
Munster: F Jones; D Howlett capt, C Laulala, J Downey, L O'Dea; I Keatley, D Williams; W du Preez, M Sherry, S Archer; I Nagle, B Holland; Dave O'Callaghan, N Ronan, P Butler. Replacements: D Varley, M Horan, BJ Botha, D Foley, CJ Stander, P Stringer, JJ Hanrahan, D Hurley.
Scarlets: M Stoddart; N Reynolds, G Maule, G Owen, A Fenby; A Thomas, G Davies; P John, E Phillips, J Adriaanse, J Ball, R Kelly, G Earle, J Edwards capt, C Price. Replacements: K Myhill, S Hopkins, S Lee, J Snyman, D Thomas, R Williams, D Newton, AWarren.