But they will be rueing their decision not to go for a drop-goal when they piled on the pressure during the final minutes of a hard and physical clash in Pool 4 of the Heineken Cup.
Had the Ospreys triumphed, Munster could not have complained because there was nothing between the sides. Outside-half Gavin Henson missed three penalties, one of them from short range, for the West Glamorgan region but, otherwise, did little wrong.
For this young and inexperienced Ospreys side to run Munster so close was no mean achievement. Many in Wales still fail to give the Irish province the credit it deserves. But the facts are: Munster have been in the last five semi-finals of the Heineken Cup, reaching two finals, and they have the best away record in the tournament's 10-year history.
Scalps on the road include Toulouse, Leicester, Stade Francais, Castres (twice), Bourgoin, Harlequins, Newport, Colomiers and Saracens.
There are six successes in France in that little lot. Quite staggering when you consider Welsh teams (Llanelli) have posted just two victories the other side of the English Channel during the same period.
Munster used that precious experience to overcome the Ospreys. They stopped giving penalties away at the breakdown following the interval after being blown up heavily before it.
Total conviction in their defence meant they didn't stray offside while they gave Ronan O'Gara more time on the ball by making hard yards up front. The Ireland outside-half was a superb controller during the second half, pegging the Ospreys back with his line-kicking.
The Ospreys threw everything at Munster with youngsters Ryan Jones and James Bater in the back row once again proving they are top-notch material. New Zealander Jason Spice provided experience at scrum-half and it was somewhat ironic his mistake, and a penalty on the stroke of half-time, were to prove telling factors.
The Ospreys were 12-6 in front but O'Gara's strike meant they went in only three points up. Four minutes after the resumption of hostilities they were behind, following a beautifully worked effort from Munster's Ireland star Peter Stringer.
A wild pass by Spice had forced Henson to minor. It meant Munster had a five-metre scrum near a touchline.
Right wing John Kelly moved infield in a ploy that dragged Shane Williams with him, allowing the nippy Stringer to exploit the space by speeding outside despairing flanker Bater for an unconverted try to give them the lead a second time, 14-12.
It lasted seven minutes, former Swansea centre Shaun Payne being penalised after not releasing following a crunching tackle from Sonny Parker.
Henson put over the long-range effort and they led 15-14. However, O'Gara regained the advantage with a penalty after the Ospreys front row were driven skyward at a scrum deep in their 22.
The Welsh outfit suffered another blow when their Samoa centre Elvis Seveali'i was shown the yellow card, for a high tackle on Kelly. A mammoth drop-goal attempt from Henson was just wide. So was a difficult penalty after a super tackle by Mustoe on Horgan following a cross-kick by O'Gara.
Shane Williams was grounded by Munster's Australian war-horse Jim Williams attempting to wriggle his way out of his own half. The Ospreys dived in at the ruck and O'Gara punished them to increase Munster's advantage to five points.
It was back to two in the 68th minute, through a Henson penalty following a 30-metre break from Spice. There was an electric atmosphere with a couple of thousand vocal Munster fans in a crowd of 10,280. Officials said it was the first time all tickets had been sold for a match at the Gnoll since the Second World War.
Ospreys supporters had reason to up the decibel count first when Henson fired them into a 3-0 lead inside two minute Spice was the victim of a high tackle.
But Munster were soon level with minutes through O'Gara - Wales prop Duncan Jones having been caught offside. They moved ahead when Ospreys tighthead Adam Jones was wrongly identified as the culprit when a scrum collapsed - Munster's Irish loosehead Marcus Horan had slipped his binding - and O'Gara found touch in the home 22.
World lock star Paul O'Connell won the line-out and O'Gara moved them ahead for the first time, 6-3, with a penalty after the Ospreys pulled down the rolling maul that followed.
But the West Glamorgan region regained the initiative within five minutes, Henson twice punishing them after O'Gara was caught in possession and failed to release.
Jim Williams was sin-binned for killing the ball at a ruck, Henson rewarding the work of the Ospreys forwards by nailing the penalty and duly did to give them a six-point advantage.
But Munster struck either side of half-time, through O'Gara and Stringer. Those moments eventually proved critical.
Andy Howell, Western Mail