With the wind in their backs in the second half they had an early opportunity reduce the deficit with a penalty from near half way. Ronan O'Gara was just wide with that but from the restart made no mistake from the Scarlets 22.
Coach Declan Kidney introduced Donncha Ryan, Peter Stringer (for Rua Tipoki) and Frankie Sheahan and almost immediately the reduced the deficit when Denis Hurley gave the scoring pass for Ian Dowling to score his second try. O'Gara's conversion from wide came back off an upright leaving Munster trailing by seven.
A Stephen Jones penalty minutes later extended the home side's lead to ten and Kidney threw on the rest of his bench as the game entered the final quarter.
With fourteen minutes remaining after Paul O'Connell had split the Scarlets defence Warwick chipped over a penalty to make it a one score game (23-16) but once again their discipline let them down and they were fortunate to see Jones' penalty fall short.
Munster peppered the Scarlets line in the closing stages and eventually Paul Warwick squeezed over in the corner but his conversion came back off the right upright.
He had one more opportunity when Lou Reed was yellow carded and Warwick's kick, from inside his own half crept over to give his side a narrow victory
Munster: D Hurley; D Howlett, L Mafi, R Tipoki, I Dowling; R O'Gara, T O'Leary; M Horan, J Flannery, J Hayes, D O'Callaghan, P O'Connell (capt), A Quinlan, D Wallace, D Leamy. Replacements: F Sheahan, F Pucciariello, M O'Driscoll, D Ryan, P Stringer, P Warwick, A Horgan.
Llanelli Scarlets: M Stoddart; D James, G Evans, N Brew, M Watkins; S Jones (capt), G Cattle; I Thomas, M Rees, D Manu, V Cooper, S MacLeod, D Jones, G Thomas, N Thomas. Replacements: P John, M Schwalger, L Reed, J Bater, L Davies, R Priestland, D Daniel.
Referee: N Paterson (Scotland)
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