OSPREYS in Swansea to maintain their unbeaten start to the season and cement themselves firmly as Conference A leaders in the Guinness Pro14.
Centre James Hook was Ospreys' try scorer with fly-half Sam Davies kicking three penalties and a conversion.
Dan Biggar came off the replacements bench late on after being rested following the British and Irish Lions tour of New Zealand. Bleyendaal's off day with the boot continued, but an eight-point half-time lead was one Munster deserved.
Bleyendaal opened the visitors' account with a penalty on nine minutes after being unsuccessful with his opening two attempts.
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.
The Ospreys hit straight back, scoring a try from their first piece of possession when Hook weaved past three defenders to touch down.
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.
Irish worldwide John Ryan will make his 100 appearance for Munster, if he takes to the field this afternoon, having made his debut against Cardiff Blues in September 2011. Darren Sweetnam, 13. Chris Farrell, 12.
Davies and Bleyendaal exchanged penalties, and two more kicks from the young Wales pivot set up a nerve-jangling finish. 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.
Ospreys: Dan Evans; Keelan Giles, Cory Allen, James Hook, Jeff Hassler; Sam Davies, Tom Habberfield; Paul James, Sam Parry, Ma'afu Fia, Bradley Davies, Lloyd Ashley, Dan Lydiate, Justin Tipuric (capt), Dan Baker.
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.