Munster failed to make it five from five in the URC after losing to the Ospreys 18-10 in Wales on Saturday evening.
Stephen Myler got the hosts off the mark with a penalty after 90 seconds. Jack Crowley, on his first start for the Province, replied with a penalty of his own on five minutes.
There was to be only two more scores prior to the half time whistle with Myler kicking over a brace of penalties either side of a disallowed Munster try as they took a 9-3 lead into the break.
This lead was extended to nine shortly after the restart as Myler added to his tally with a fourth penalty.
Munster brought themselves back into the game with Craig Casey bundling over after a strong lineout maul. But Crowley was unable to kick the conversion with Ospreys maintaining the lead.
But Munster couldn’t build on that score as another pair of Myler penalties moved them eight clear heading into the final ten minutes.
Ben Healy did have a chance to earn a bonus point with the clock in the red but his long range penalty just sailed wide as Ospreys claimed a deserved win.
Munster now must wait over a month until their next game as they travel to South Africa to take on the Vodacom Bulls on November 27.