Four years on from the first of their two winning finals in Dublin, the birds of prey from Swansea are back on their lofty perch, having confirmed their right to be there with an impressive declaration of championship intent.
The Ospreys of today could hardly be more different to those of yesterday. The 20 players involved in beating Munster at Thomond Park contained only three survivors from the victorious squad at the RDS in May 2010 - Andrew Bishop, Dan Biggar and Alun Wyn Jones.
When the rugby recession hit South Wales, straps had to be tightened all across the 60-mile rugby belt from Llanelli in the west to Newport in the east. The Ospreys lost more than the other three Welsh regions if only because they had more to lose.
Mike Phillips, Lee Byrne and James Hook went to the green fields of France, Shane Williams and Jerry Collins to Japan and three more across the Severn Bridge - Paul James, Jonathan Thomas and Ryan Jones. Marty Holah went home to New Zealand and Tommy Bowe back whence he came, to Ulster.
Two more Grand Slammers flew the nest last summer - Adam Jones to Cardiff Blues, Richard Hibbard to Gloucester. Even Toulon would be hard pushed not to feel the pinch at losing two-thirds of the Lions' Test front row, never mind a team trying to make do on a fraction of the French champions' budget.
The Ospreys ignored the doubters because they knew the quality of the younger models rolling off the assembly line. Having sown the seeds a while back, they are now reaping the rewards of the region's philosophy, a change from buying big-name players to producing their own.
The Ospreys' Vision is built on 'development from within - Ospreys supporting Ospreylia, Ospreylia supporting the Ospreys'. Their mantra calls for the pursuit of excellence, the exclusion of 'bulls***' and the need for collective enjoyment.
Of the match-day 23 in Limerick, a large majority have come up through the ranks - Dan Evans, Andrew Bishop, Eli Walker, Biggar, Rhys Webb, Nicky Smith, Scott Baldwin, Alun Wyn Jones, Justin Tipuric, Dan Baker, Duncan Jones, Cai Griffiths, James King, Morgan Allen and Sam Davies.
All but four of those on duty in Munster are Welsh or Welsh-qualified, among them the uncapped wing Hanno Dirksen and the equally-uncapped veteran Cornishman, Joe Bearman.
Twelve are natives of Ospreylia, the title which now goes with the territory following the amalgamation of the All Whites of Swansea and the All Blacks of Neath in 2003. Evans, Walker, Biggar, Webb, Smith, Baldwin, Alun Wyn Jones, Tipuric, Baker, Duncan Jones and Davies are all native Ospreylians.
The Welsh element at Thomond would have been stronger had international tighthead Aaron Jarvis not been forced into a late withdrawal.
Moldovan prop Amitri Arhip responded to the emergency, playing his part in tandem with South African lock Rynier Bernardo, English centre Josh Matavesi and Canadian wing Jeff Hassler.
Not many can claim the distinction of scoring the visiting team's solitary try in a victory at Thomond Park, a second defeat there in the opening month for a Munster squad now faced with the daunting task of tackling Leinster at the Aviva Stadium on Saturday.
Hassler's third try in four matches this season resulted this week in the 23-year-old from the prairie town of Okotoks in Alberta being rewarded with a brand new three-year contract. In coming from behind a second time, the leading Welsh challengers came through a severe test of their mental fortitude.
As the ever-dependable Biggar, whose three second-half penalties proved decisive, put it: "We toughed it out."
Plenty more of the same quality will be required in the months to come and nobody is more aware of that than Biggar, at the tender age of 24 an old-hand in the context of the Ospreys revival.
Only the Warriors have matched them, win for win, over the first four weeks of the campaign. Glasgow's finest brought Connacht's winning start to a stop at Scotstoun, a second successive bonus-point win raising their try total to 15 compared to the Ospreys' 17.
And while they set a fast pace at the top, one team got off the mark in some style. The Dragons, restricted to a brace of losing bonus points from narrow defeats by Connacht and the Ospreys, claimed all five against Treviso at Rodney Parade with Hallam Amos leading the way.
There is a case for the outstanding performance of the weekend to be found in much the same lower end of the table. Zebre 13, Ulster 6 is already a strong contender for the biggest hit on the Richter Scale of shocks.
The Italians, pointless after the first three matches, had shipped more than 30 points at the Kingspan Stadium 15 days earlier. Ulster landed in Parma reinforced by an unbeaten start and 11 tries from their three matches.
Before Zebre went out to deliver a mighty reminder that they still have what it takes to beat the best, they would surely have drawn inspiration from the fact that Ulster had found the Stadio XXV Aprile a tricky place to negotiate over the last two seasons.
They managed just the one try in winning there 19-11 last November. Twelve months earlier, Zebre managed the incredible feat of outscoring the Irish province 4-1 on tries only to lose 25-27. Ulster, therefore, would have seen the writing on the wall and responded accordingly.
The contest turned out to be a tale of the respective tightheads. While Declan Fitzpatrick went for the earliest of baths, his Zebre opposite number, Dario Chistolini, claimed the only try of a stunning match.
And Kelly Haimona kicked three goals to plunge the 2012 European Cup finalists into hotter water than the sulphur springs of his native Rotorua.
The headline in La Gazzetta Dello Sport said it all: 'Finalmente festa Zebre: Ulster battuto 13-6.'
And who should be next up at the Stadio XXV Aprile? Why, none other than the table-topping Ospreys…
Follow us on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the GUINNESS PRO12.
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland