A full-strength Munster claimed their first win of the season as their pack dominated the reigning champions.
Munster (5) 19
Tries: Quinlan, Cullen, Leamy
Cons: O'Gara (2)
Scarlets (3) 13
Tries: Evans, Phillips
A 40m rolling maul gave Alan Quinlan the opening score at Thomond Park.
Second-half tries followed from Christian Cullen and Denis Leamy, but the Scarlets rallied to deny the home team a fourth, bonus-point score.
The visitors' recovery saw tries from Garan Evans and Mike Phillips that gave them a bonus point for finishing within seven points.
Munster had the better of the opening exchanges, without being able to make their dominance tell on the scoreboard.
The Scarlets' defence was desperate and determined, epitomised by Andy Powell's last-ditch tackle to deny Cullen as the full
-back flew for the corner.
The home side went back to basics in the wet, treacherous conditions, as the Scarlets struggled to hold their imposing pack.
They set up a driving maul that rolled relentlessly forward from 40m out, the visitors unable to stop Quinlan dropping over
for the opening try after 26 minutes.
The Scarlets then had tight-head John Davies sin-binned for dropping a scrum, but their 14 men rallied before the break.
Temporary replacement prop Phil John, back from a long absence with a broken ankle, impressed at the scrum and helped force
two Scarlets penalties.
Gareth Bowen slotted the first well but missed a simple second to deny the visitors a half-time lead.
Munster tightened their grip after the break and gained good field position with a penalty after Powell's dreadful high
tackle on Paul O'Connell.
The forwards battered at the Scarlets' line, delivering fine ball that allowed Anthony Horgan to scythe through the defence,
before feeding Cullen for a simple score.
A good touch from Cullen helped set up the third try, the forwards recycling well to free Leamy for a try on the right wing.
The under-fire Scarlets hit straight back through their exciting backs, Tal Selley breaking well before Phillips fed Evans, the full-back showing his pace to cross in the corner.
The double act was repeated on 80 minutes as Evans ran from deep in his own half before sending Phillips in at the corner to salvage a point for the Welsh team.
"We were optimistic coming here and thought we had the chance of a result," said Scarlets coach Gareth Jenkins.
"In the end, the result has gone the way of the performance - they haven't dominated or outplayed us, but we made too many errors.
"We showed spirit, determination and creativity, but there was not enough composure to expect a win."
Munster: C Cullen; J Kelly, M Mullins, R Henderson, A Horgan; R O'Gara, P Stringer; M Horan, F Sheahan, J Hayes, D O'Callaghan, P O'Connell, A Quinlan, D Leamy, A Foley.
Replacements: G McIlwham, J Flannery, T Hogan, D Wallace, M Prendergast, P Burke, J Storey.
Scarlets: G Evans; A Havili, M Watkins, M Taylor, T Selley; G Bowen, M Phillips; I Thomas, M Rees, J Davies, V Cooper, A Jones, S Easterby (capt), G Thomas, A Powell.
Replacements: P John, C Hawkins, C Wyatt, J Mills, D Peel, A Thomas, R Jones.
Referee: Malcolm Changleng (Scotland)