Munster’s bonus-point win over title rivals Glasgow Warriors the previous week had seemingly put Foley’s side in pole position in the battle for a play-off place going into the most critical stage of the campaign.
But defeat to the Ospreys now leaves them just four points ahead of fifth-placed Leinster, and it could have been a lot worse, had Matt O’Connor’s side not also lost in Wales on Saturday evening.
Munster had been the last side to beat the Ospreys at the Liberty Stadium more than 12 months ago and they had been hopeful of a repeat performance given the stuttering league form of the Welsh region.
The Ospreys were without a win in three Pro12 games but there was little sign of that poor form as they comfortably dispatched the travelling Munster men.
Even before flanker Dave O’Callaghan was sent to the bin for a high tackle on full-back Dan Evans, the Ospreys had been building a steady lead, but once Munster went down to 14 men, the home side racked up 11 crucial points that took the game away from the visitors.
“It’s baffling for us where that performance came from,” admitted Foley. “It wasn’t in our training in the week, it wasn’t in our preparation but then to go out and give away that many penalties in the game, you are going to get punished.
“We conceded one try in the game when we had a player in the sin bin but I think we had six penalties to zero at that stage.
“I can’t complain about the referee, I thought the penalties were fair and within reason, it was down to our lack of control and you expect to get punished off the park by the referee, and we did.
“Dave went around the neck but then pulled out but it was more of a cumulative thing and we were on our last warning at that point.
“The next one who did something was going to be gone and unfortunately it was Dave, and they punished us when we went down to 14.”
It was the Ospreys’ first league double over Munster since the 2011/12 campaign, having come out on top when the two sides met at Thomond Park at the end of September.
Dan Biggar and Rhys Webb had orchestrated a 19-14 victory that day but this time without the Wales internationals it was their half-back deputies Sam Davies and Tom Habberfield who guided the Ospreys to a much-needed win. Outside-half Davies, son of former Wales international and Scarlets coach Nigel, kicked 21 points and set up the Ospreys’ try for No.8 Dan Baker with a mature display.
Two tries in the final 10 minutes from Donnacha Ryan and Keith Earls salvaged some respectability for the visitors but in truth, it was nothing more than a consolation against a dominant Ospreys side.
Foley and Munster will now get three weeks to ponder just what went wrong before they welcome Connacht to Thomond Park when they will hope to get their play-off challenge back on track.
Munster’s run-in appears easier, including three home games against Connacht, Treviso and the Newport Gwent Dragons, to give them the edge over their top-four rivals. When compared to the Ospreys, who have to travel to Treviso, play local rivals Cardiff Blues at the Millennium Stadium and welcome Glasgow to the Liberty, it does make for good reading for Foley but only if they can reproduce the form that saw them win four of their first five Pro12 fixtures of 2015.
“You’d like to get straight back on the horse but we’ve got three weeks off before we play Connacht and we have to make sure we right the wrongs from this game,” added Foley.
“We have to make sure we are prepared for Connacht because there is still an awful lot to play for in the season. It’s vital we get into the top four and there are five teams vying for four spots, you don’t want to be one to miss out.”
OSPREYS: D Evans (B John 40); T Grabham, J Spratt, J Matavesi, H Dirksen, S Davies, T Habberfield (M Roberts 69); R Bevington (N Smith 47), S Otten (M Dwyer 70), A Jarvis (D Arhip 47), L Peers (R Thorton 47), T Ardron, J King, J Tipuric (capt), D Baker (M Allen 72).
MUNSTER: JJ Hanrahan (A Smith 51); F Jones, K Earls, D Hurley (capt), R O’Mahony (A Conway 70); I Keatley, D Williams; D Kilcoyne (J Ryan 51), E Guinazu (K O’Byrne 60), BJ Botha (S Archer 60), Donncha O’Callaghan (D Ryan 60), B Holland, Dave O’Callaghan, S Dougall (J O’Donoghue 48), CJ Stander.
Referee: M Mitrea (FIR).