Ospreys (9) 21
Pens: Hook 7
Munster (11) 25
Tries: Mafi, O'Leary Pens: Warwick 2, Doyle 2, O'Leary
Half-back Tomas O'Leary was in superb form for Munster
An all-action display from Tomas O'Leary earned Munster an important away win against Magners League title rivals the Ospreys on Friday night.
The scrum-half prevented what seemed a certain Ospreys try in the first half, then scored himself in the second.
O'Leary then capped that by switching to fly-half and kicking a penalty.
The Ospreys had to rely on the boot of James Hook for all their points, the fly-half kicking seven out of eight penalties as Munster defended fiercely.
Munster started confidently at the Liberty Stadium and within four minutes had broken through the Ospreys' defence for the game's opening try.
Paul O'Connell provided the beef to widen a half-break by his backs, allowing scrum-half O'Leary quick ball to launch his support down the blind side.
Quick hands, swift pace and good running lines gave Lifeimi Mafi just enough space to squeeze in at the right corner flag, despite Lee Byrne's despairing tackle, for an unconverted try.
We concentrated on keeping it basic and keeping it tight you know and the forwards delivered
Munster scrum-half Tomas O'Leary
Hook soon got the Ospreys on the scoreboard with a penalty, but Paul Warwick replied to restore Munster's five-point lead.
The opposing fly-halves exchanged penalties again as the Magners League top two bumped and probed one another's defences.
Hook ended the sequence by missing his next kick, shaving the outside of the right post from 35 metres away and straight.
The Ospreys backs were starting to click, though, and Andrew Bishop did a fair impression of more lauded team-mate Gavin Henson - rested for this match along with skipper Ryan Jones - with a sublime pop-pass.
Centre partner Sonny Parker took the ball in his stride to lope through the Munster line and send Jon Vaughton haring towards the left corner.
The wing forced his way past Mafi only for O'Leary's superb covering tackle to force Vaughton into touch just short.
Shane Williams on the other wing, restored to active duty after injury, also caught the eye down the right in tandem with the seemingly always excellent Byrne.
Munster suffered a blow when Warwick was caught in the face by a stray leg and with no Ronan O'Gara on the bench had to turn to Conan Doyle, an elementary replacement at fly-half.
With three minutes of the half remaining, more Ospreys pressure earned another kickable chance that this time Hook sent between the sticks to cut Munster's lead to 11-9 at half-time.
A fourth successful Hook kick followed soon after the restart, this one slightly against the run of play, to put Ospreys into the lead for the first time in the match.
The Wales fly-half followed that up with a superb penalty from a metre inside his own half, which soared straight and true to bisect the Munster posts.
But Munster reclaimed possession from the kick-off and drove upfield, tempting the Ospreys to give away another penalty as they slowed things down illegally at a ruck and Doyle opened his account with the resulting kick.
David Wallace almost claimed a second try for Munster when he popped out the back of a ruck and raced into the Ospreys' 22.
However, the flanker had outstripped his support and was forced to hold on in the tackle.
Williams, always alert, opted to tap the penalty and picked a spot in the Munster line containing two forwards, racing between O'Connell and Jerry Flannery.
Hook and Vaughton were alive to the adventure and their support took Ospreys within sight of the Munster posts, only for Ian Dowling to cynically reach into the ruck to kill the ball.
The Munster wing was rightly sin-binned for the offence and Hook struck the penalty.
The tables were turned soon after, though, as Ospreys flanker Steve Tandy repeated the crime, the open-side getting an equally deserved yellow card and Doyle cutting Munster's deficit to 18-17.
Another Munster score soon followed, the forwards driving to suck in the defence before the ball was spun wide to Mafi, who was stopped but popped the pass for O'Leary to shunt over.
Doyle missed the conversion and was substituted soon after for Peter Stringer, the all-action O'Leary shifting to stand-off and taking over the kicking duties.
He soon bagged his first penalty to give Munster a 25-18 lead with 11 minutes remaining.
A seventh Hook penalty of the night brought Ospreys to within four points once more and set up an edgy last 10 minutes.
But Munster continued to defend stoutly and when in possession patiently ground down the clock for an important win in Swansea.
Ospreys fly-half James Hook:
"Munster, in fairness, spoilt everything at the breakdown for us and when we wanted quick ball we couldn't get it for the backs.
"There were opportunities out there for us but unfortunately they slowed the ball down and we couldn't play with it.
"I was happy with the kicking today, probably the one I missed should have gone over but never mind."
Munster scrum-half Tomas O'Leary:
"It's brilliant, we've got a great pack and traditionally we've always been strong.
"So this week we concentrated on keeping it basic and keeping it tight you know and the forwards delivered.
"It was an easy ride to be behind them to be honest."
Ospreys: Lee Byrne; Jonny Vaughton, Sonny Parker, Andrew Bishop, Shane Williams; James Hook, Mike Phillips; Paul James (capt), Richard Hibbard, Cai Griffiths, Alun Wyn Jones, Jonathan Thomas, Tom Smith, Steve Tandy, Filo Tiatia.
Replacements: Huw Bennett for Hibbard (56), Ryan Bevington, Lyndon Bateman for Thomas (70), Marty Holah for Tandy (76), Rhys Webb, Dan Biggar for Parker (45), Kristian Phillips.
Munster: D Hurley; D Howlett, B Murphy, L Mafi, I Dowling; P Warwick, T O'Leary; F Pucciariello, J Flannery, J Hayes; D O'Callaghan, P O'Connell capt; A Quinlan, D Wallace, D Leamy.
Replacements: D Fogarty, T Ryan for Pucciariello (74), M O'Driscoll for Quinlan (60), J O'Sullivan for Leamy (58), P Stringer for Doyle (72), C Doyle for Warwick (38), T Gleeson.
Referee: Andy Macpherson (SRU).