Ospreys' James Hook takes a high shot from Munster's Lifeimi Mafi
Ospreys: (13) 20
Tries: Hook, Marshall
Cons: Hook (2)
Munster: (5) 12
Tries: Ryan, Carney
Ospreys laboured to a Magners League victory over Munster in a disjointed match at the Liberty Stadium.
Fly-half James Hook scored all the Ospreys points in the first half with a converted try and a penalty.
Lock Donnacha Ryan's try kept Munster in touch, but scrum-half Justin Marshall's converted try late in the second half took Ospreys clear again.
Munster ended the scoring when winger Brian Carney crossed in stoppage time, converted by replacement Ronan O'Gara.
The Ospreys suffered an early setback in the third minute when they were forced to make two back-row substitutions.
First a very groggy Andy Lloyd had to be helped off after appearing to clash heads with Alun Wyn Jones, and then Steve Tandy was forced off with a shoulder injury
Early indications were that both could be ruled out for the rest of the season.
After the early disruption, the omens looked good for an entertaining encounter as both sides scored impressive tries in the opening 15 minutes.
Hook drew first blood for the Ospreys as he side-stepped past Ryan's attempted tackle after a period of heavy pressure.
Ryan quickly atoned for his error by scoring at the other end after scrum-half Tomas O'Leary had sliced threw the home defence from the half-way line.
But the game deteriorated from there as the Ospreys struggled to make their dominance pay, Hook's penalty the only other score before the break.
The fans had to wait until the 67th-minute for the next score as replacement Marshall burst clear from a lineout to score, with Munster complaining of obstruction.
It was the home side who felt aggrieved in the closing stages as Carney looked suspiciously off-side when O'Gara delivered a pin-point cross-field kick.
But the burly winger did not wait for the whistle, and showed impressive strength and pace to beat the Ospreys cover to score in the right corner.
Ospreys: Terblanche; Vaughton, Parker, A Bishop, S Williams; Hook, Spice; James (capt), Bennett, Griffiths, Cockbain, A W Jones, Lloyd, Tandy, R Jones.
Replacements: Walker for Vaughton (65), Marshall for Spice (61), B Williams for Bennett (61), A Jones for Griffiths (57), Thomas for Lloyd (3), Pugh for Tandy (3).
Not Used: Connor.
Munster: Lawlor; Carney, Murphy, Mafi, Horgan, Manning, O'Leary, Pucciariello, Sheahan, Buckley, O'Callaghan, D Ryan, Quinlan, O'Sullivan, Foley (capt).
Replacements: Earls for Horgan (65), O'Gara for Manning (54), Horan for Pucciariello (54), Flannery for Sheahan (65).
Not Used: O'Connor, Coughlan, O'Meara.
Ref: David Changleng (Scotland).