Munster recorded their first win in six meetings with the Ospreys as they maintained their lead at the top of the RaboDirect PRO12.
Rob Penney's men head into the November international break as league leaders thanks to three penalties from Ian Keatley and a fourth successful kick from replacement JJ Hanrahan.
The province forced the issue for most of the opening 40 minutes at Thomond Park, but only led 6-3 at the breaks as Matthew Morgan replied to two early kicks from Keatley.
Keatley and Hanrahan moved Munster into a 12-3 lead by the 68th minute, but Morgan secured a losing bonus point for the Welsh region with an injury-time penalty.
Keatley flighted over the opening points from a fifth minute penalty - prop Marc Thomas was penalised for a binding offence - as much-changed Munster quickly settled to their task.
Morgan Allen and Tito Tebaldi were both prominent for the visitors in the early stages, albeit in a defensive capacity as the men in red maintained their strong start.
CJ Stander was busy in the contact area, winning a penalty wide out on the left which Keatley put wide.
The Munster out-half was back on target in the 22nd minute, slotting over from closer in after Joe Bearman was penalised for side-entry at a ruck.
Strong carrying from Allen and Ben John got Morgan into position for his first penalty success of the night, with Stander the guilty party for not rolling away.
The first half skipped along at a steady pace but neither try-line was tested until late on when Ivan Dineen stepped inside Andrew Bishop's tackle to seemingly score to the left of the posts.
However, Dineen's effort was ruled out as television match official Jude Quinn ruled that the preceding Ospreys scrum, which saw the ball squirt out of the tunnel and into Duncan Williams' grasp, had not been completed.
The Ospreys' general play improved on the resumption, with winger Aisea Natoga getting involved, while a couple of decent Munster moves were ended by interceptions.
A double movement prevented Tebaldi from breaking the try deadlock and Keatley had the distance but not the accuracy from a long range 52nd minute penalty.
He made no mistake with his next shot at the posts though and despite lacking the necessary penetration, Munster, with captain Damien Varley in man-of-the-match form, continued to dictate play for the most part.
A late challenge by Ospreys replacement Hanno Dirksen on Johne Murphy drew a penalty which Hanrahan converted from the 22, widening the margin to nine points as Munster overcame the Ospreys for the first time since the 2011 league semi-final in Limerick.
Morgan miscued a penalty from a tough position on the left and also sent a drop goal wide, however a Ronan O'Mahony error gave the Ospreys a late five-metre scrum and they earned a penalty which Morgan slotted for the bonus point.