Munster held off a second-half comeback from Ospreys to register their third straight Guinness Pro14 victory in torrential rain at the Liberty Stadium.
Rassie Erasmus' side scored two first-half tries through former Stormers lock Jean Kleyn and winger Darren Sweetnam, with Tyler Bleyendaal adding 11 points from the boot.
Munster were dominant physically before the break and a cracking try from former Wales global James Hook and 11 points from the boot of out-half Sam Davies were not enough to give the Ospreys victory.
Wales worldwide Dan Lydiate was a late inclusion for his first appearance since injury knee ligaments in November previous year.
Dan Biggar came off the replacements bench late on after being rested following the British and Irish Lions tour of New Zealand.
Bleyendaal led his side in at half-time with a 15-7 lead but it could have been a bigger advantage.
Bleyendaal finally found the target with his third penalty shot from in front of the posts on 10 minutes after Ospreys had collapsed a scrum up against a big Munster pack.
But that was Ospreys' last significant attack of the half as they had to deal with an accurate Munster kicking game and wave after wave of attacks.
Munster started strongly, consigning the hosts to their own 22 and had a try disallowed for a forward pass after Jaco Taute had run on to a Tyler Bleyendaal pass. Bleyendaal converted the first of those efforts to send his team into the break 15-7 to the good.
Fly-half Davies and Bleyendaal swapped penalties at the start of the second half as Ospreys who, brought Nicky Smith and Scott Baldwin on at half-time, started to claw their way back into the contest. Munster kept the ball in the forwards and it paid off. Bleyendaal's third penalty sealed the win and although there was no bonus point, this success would have pleased Erasmus no end.
Munster: Conway (Zebo 64); Sweetnam, Farrell, Taute (R Scannell 55), Wootton; Bleyendaal, Williams; L O'Connor (Cronin 52), Marshall (N Scannell 52), Archer (Ryan 52), Kleyn, Holland, S O'Connor (Copeland 66), O'Donnell, O'Donoghue.