About 95 minutes had elapsed since referee Jerome Garces had started the game at the Liberty when Ronan O’Gara lined up his final kick and when he nervelessly, no surprise, dissected the posts it gave Munster a victory they richly deserved last Saturday in front of a 9000+ crowd
It was a win that didn't seem likely when minutes earlier, James Hook had landed a penalty to give his side a 20-19 win but to their great credit, Munster fought their way into the Osprey's 22, lined O'Gara up for two drop goal attempts, the second taken only after Garces had already awarded the penalty.
There were shades of that last gasp penalty win over Leinster although on this occasion the kick was much closer to the posts and there was no time for a response from the home side who now must rely on others to get them a semi-final place.
At the end of a lively first half Munster led 10-3 thanks to a 33rd minute David Wallace try and the boot of O'Gara. They had carved out two clear chances, first Keith Earls losing the ball over the line after he'd engineered the chance and Lifeimi Mafi doing likewise after he'd almost latched onto a clever O'Gara kick.
By the same token it needed a superb Conor Murray to deny Hook at the corner but overall Munster deserved their lead.
O'Gara extended it with an early second half strike before an Alun Wyn Jones try, off a rolling maul and a penalty try, both converted by Dan Biggar, left the home side in the driving seat.
Two further O'Gara penalties edged Munster in front before Hook's effort on the stroke of full time seemed the likely winner.
But Munster had other ideas and their tireless pack worked the space to set up their out-half for the winner with the last kick of the game.
Ospreys: Byrne; N Walker, Bowe, Hook, Fussell; Biggar, Webb; Bevington, Hibbard, A Jones, Gough, AW Jones, Tipuric, Holah, Thomas. Replacements : Bishop for Byrne (29 mins), Parker for Biggar (73 mins), M Phillips for Webb (74 mins), James for Bevington (55 mins), D. Jones for Gough (17 mins), Collins for Holah (73 mins).
Munster: Jones, Howlett, Mafi, Warwick, Earls, O'Gara, Murray, Horan, Varley, J. Hayes, D. O'Callaghan, Nagle, D Ryan, Wallace, Coughlan. Replacements : Zebo for Warwick (66 mins), Stringer for Murray (63 mins), du Preez for Horan (50 mins), Sherry for Varley (63 mins), Buckley for J Hayes (42 mins).
Referee: Jerome Garces (France).