An injury-time Ronan O'Gara penalty condemned the Ospreys to a 22-20 defeat and a fourth straight loss to keep them out of the Magners League play-off places in a hard-fought clash at the Liberty Stadium.
The Ospreys outscored leaders Munster two tries to one, but the visitors were indebted to 17 points from O'Gara with five penalties and a conversion. It is the only second time in their history that the Ospreys have suffered four consecutive defeats in a season.
The match was locked at 0-0 going into the second quarter and the best chance of a try fell to Munster, who worked good line-out ball out to the left where Keith Earls knocked on as he was trying to gather the ball over the line.
In the 20th minute an encouraging attack saw hooker Richard Hibbard put James Hook over in the left corner but the try was ruled out on the intervention of the television match official for a foot in touch. But on 23 minutes the deadlock was broken when O'Gara kicked a penalty from the 22. And Munster followed that up with a try on 32 minutes courtesy of openside flanker David Wallace, who went on a bulldozing run over the line for a try converted by O'Gara.
The Ospreys finally got on the scoreboard four minutes later with a Dan Biggar penalty. But it was not a good start to the second half for the Ospreys with O'Gara restoring Munster's ten-point lead with a penalty.
Biggar was just wide of the mark with a penalty attempt four minutes later, but the Ospreys got right back in the contest by scoring two tries in the space of seven minutes. On 52 minutes skipper Alun-Wyn Jones was on hand to go over for a converted try from a forward drive which cut Munster's lead to 13-10.
That seemed to inspire the Ospreys as wing Richard Fussell went on an impressive run which put the region in a good territorial position. And from there they had a series of scrums from which they earned a penalty try to go 17-13 ahead.
The reliable boot of O'Gara restored the Munster lead with two penalties on 69 and 73 minutes. However, Hook, in his last home game before he joins Perpignan, stole back the lead with his own penalty four minutes from time, while O'Gara saw a drop-goal attempt screw wide of the target with time running out.
But O'Gara made amends in injury time by putting over the winning penalty after the Ospreys, who had had Jerry Collins sin-binned for a dangerous tackle, had been caught offside.