The reigning champions had hoped to become the first side to defend their Magners League crown but a try in either half from Munster centre Danny Barnes saw those hopes dashed at the semi-final stage.
Richard Fussell crossed for a late consolation for the Ospreys, while Ronan’ O’Gara and Dan Biggar exchanged the remaining points.
The Ospreys could have taken the lead on eight minutes following a rare foray into the Munster half, but James Hook was off target with his drop-goal attempt.
Instead it was the top seeds who put points on the board first with 13 minutes gone thanks to the boot of Ireland fly-half O’Gara, following an Ospreys’ scrum offence.
Moments later O’Gara struck the uprights with his second penalty but the Irish province did extend their lead shortly after the half-hour mark. After David Wallace was tackled just short, the ball was spread through the hands of the Munster backs for Barnes to race over in the corner.
Biggar landed a long-range penalty on 37 minutes to hand the Ospreys their first points and leave them looking to overturn an 8-3 deficit at the interval.
But Munster restored their lead on 46 minutes thanks to the boot of O’Gara and things got worse for the Ospreys when hooker Richard Hibbard was sent to the sin-bin within minutes of coming on as a replacement.
The Ospreys hit back through Biggar’s boot on 55 minutes to reduce arrears to 11-6 but they were struck a hammer-blow just moments later when Barnes crossed for his second try. The young centre charged-down Fussell’s clearance kick and collected comfortably to score beneath the posts.
O’Gara added the extras to hand Munster a commanding 18-6 lead which they never looked like relinquishing despite Fussell’s late effort.
