Munster held off a second-half comeback from Ospreys to register their third straight Guinness Pro14 victory in torrential rain at the Liberty Stadium.
The Irish province dominated most of the match and scored two tries to one but Ospreys were able to register a losing bonus point.
Conference A leaders Munster were indebted to try scorers Jean Kleyn and Darren Sweetnam, with captain Tyler Bleyendaal kicking 11 points, but he also missed two penalties and a conversion.
Centre James Hook was Ospreys' try scorer with fly-half Sam Davies kicking three penalties and a conversion.
Wales international Dan Lydiate was a late inclusion for his first appearance since injury knee ligaments in November last year.
Dan Biggar came off the replacements bench late on after being rested following the British and Irish Lions tour of New Zealand.
Munster made one change from their 51-18 win over Cheetahs with Bleyendaal coming in to captain the side.
Bleyendaal led his side in at half-time with a 15-7 lead but it could have been a bigger advantage.
It was not a great early return for Bleyendaal who missed two easy penalty shots on three and seven minutes with his side dominating the opening minutes with possession and territory.
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.
Against the run of play Ospreys, who had lost 31-10 in Glasgow last week, scored a try two minutes later when Hook weaved his way over from the 22 for Sam Davies to convert.
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 scored the first of two first half tries on the 20-minute mark when Kleyn crashed over after the Irish pack went on a rumble from a line-out. Bleyendaal converted as the visitors led 10-7.
And three minutes from the interval wing Sweetnam went over on the right after the lively Chris Farrell broke through with significant contributions from flanker Sean O'Connor and centre Jaco Taute.
Bleyendaal failed with the conversion attempt from wide out.
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.
And two well-struck Davies penalties on 57 and 64 minutes reduced Munster's lead to two points.
But a third Bleyendaal penalty three minutes from time gave Munster some much-needed breathing room.