Tries from Richard Fussell and Rhys Webb helped an understrength Ospreys side to a famous 19-13 victory over Munster at the Liberty Stadium.
Outside-half Matthew Morgan put over three penalties, while Munster managed a losing bonus point with their try coming from wing Doug Howlett.
The Ospreys were without 19 players for the clash, including seven on Wales duty against Australia. Despite those absences, the Ospreys were still able to field seven internationals in a game which pitted second against third in the league.
Munster had the first chance to open the scoring but outside-half Ian Keatley was off target with penalty shots on seven and ten minutes. The Irish province's early dominance suffered a setback when referee Peter Allan sent Irish hooker Damien Varley to the sin-bin for some over-vigorous use of the boot at a ruck.
And with the man advantage the Ospreys had their first scoring opportunity on 19 minutes, but Morgan was short with a long-range penalty attempt.
From a ruck offence, Morgan broke the deadlock on 22 minutes with a penalty goal from 30 metres out. But the Ospreys had their lead cancelled out by a Keatley penalty three minutes later. And, back to 15 men, the Munstermen went into the lead with a try for former New Zealand wing Howlett when he latched on to centre Will Chambers' kick over the line.
Despite the setback, the Ospreys reduced the Munster lead to four points with a second Morgan penalty on 34 minutes.
The Ospreys made a dramatic start to the second half, scoring two tries in the space of five minutes. First Webb sent wing Fussell in before the scrum-half himself turned from provider to scorer, scorching in after taking a quick tap penalty.
The two scores prompted Munster to unload their bench as they sent on Lions Paul O'Connell and Ronan O'Gara. The latter made an instant impact, putting over a penalty on 63 minutes, but that was almost immediately cancelled out by Morgan's third penalty shot.
As the match moved into its business end Munster encamped themselves by the Ospreys line with a series of scrums, but the home side held out to deny the Irishmen.