A TORRENTIAL middle third nearly left Gloucester submerged at the sodden Liberty Stadium.
Forget the weather though – the downpour that cost the Cherry and Whites was conceding 20 unanswered points.
As sloppy as the Swansea pitch was sodden, Nigel Davies' men simply could not clear their lines smartly enough, nor stay sufficiently disciplined to grind to another tight victory.
The customary last-gasp heroics turned a 26-13 deficit into an improbable and in truth undeserved 27-26 lead.
But then the Ospreys took advantage of another woeful exit strategy, to use the coaches' shorthand jargon, and powered back for rightful victory.
Powerful Kiwi centre Tim Molenaar was left lamenting the fact that the only leaks on a stormy night were those in Gloucester's defence and elementary clearance structure.
And now he believes the Cherry and Whites have to harness their trademark resilience – and turn it into full-contest dominance rather than last-ditch turnaround salvage jobs.
"We made sure we left with respect," admitted the 31-year-old former Nottingham line-breaker, "but we need to start being more than just resilient.
"We need to make sure we start leading these games all the way through.
"The confidence is definitely there, and the boys will fight right until the end, but we just need to get ourselves in better positions so that when we go into the closing stages we can be in more command, rather than trying to claw our way back into things.
"We've got to be a bit tidier, a bit smarter.
"We made some silly errors, but we did battle back and we can be pleased with that aspect.
"The challenge now is to learn from our shortcomings and sharpen up.
"We lost our way in that third quarter – at least we managed to come back from that, but we certainly let ourselves down after half-time.
"We never give in, the score was irrelevant for us. We just needed to get back in the game, get the respect back.
"Potentially we should have held on at the end, but we nearly got out of jail there.
"The team spirit's there, and now we've got to build on the technical sides of things."
Yann Thomas' opening try on 27 minutes after a lineout drive was just reward for a fine night in both tight and loose, cut short by injury early in the second half. The loosehead prop typified Gloucester's scrummage dominance, that grew and grew with the contest.
If only the rest of their game could have matched that resolve and regimen.
Ospreys fly-half Matt Morgan's three penalties and two drop-goals snatched a first lead for the home side on the stroke of half-time.
And as the third quarter bit, the Ospreys turned their 15 points into 26, through another Morgan penalty, a score for wing Tom Grabham – and a second-touch penalty from Nigel Davies' son Sam.
Almost every time Gloucester tried to clear their lines they failed to do so cleanly, and that completely undermined an otherwise reasonable full debut for Billy Burns. His departure from the field with a serious-looking shoulder injury just shy of the hour compounded a frustrating night.
If he is sidelined for a while, the 18-year-old Academy man must content himself with the fact he is progressing nicely.
Just when Gloucester looked bound for ignominy though, the Cherry and Whites conjured that Nigel Davies-era trademark resilience.
Dan Murphy capped one strong forward sequence with a good try, and in next to no time the visitors had registered a penalty try from a barnstorming driving lineout.
But perhaps Gloucester had made a fool of fickle fate once too often in their early-season habit of sneaking wins from gritty performances.
So that 27-26 lead last little more than a minute.
Another botched restart clearance later, Ospreys blasted into centre-field from a lineout tail peel – and number eight Morgan Allen was driven over at serious pace.
Davies Junior slotted the conversion and full-time followed shortly afterwards – leaving the Kingsholm men deflated.
Gloucester coaches Davies and Paul Moriarty watched their sons lock horns, Sam for Ospreys and Ross for the Cherry and Whites, both youngsters impressing.
The wrong Davies had the final word from a Gloucester view, but this loss was all down to inaccuracy rather than family ties.
OSPREYS: R Jones, T Grabham (N Edwards, 69), B John, J Spratt, W Price, M Morgan (S Davies, 61), R Webb (T Haberfield, 61), M Thomas, M Dwyer, J Rees ( N Thomas, 68), L Peers (R Hughes, 72), J King, G Stowers, S Lewis (capt), M Allen. Unused: S Otten, N Smith, A Ellis.
GLOUCESTER: M Thomas, S Monahan, D Locke, T Molenaar, I Clark, B Burns (D Lewis, 54), D Robson, Y Thomas (D Murphy, 45), T d'Apice (K Britton, 58), D Chistolini (T Heard, 69), E Stooke, W Graulich, R Moriarty, M Cox, P Buxton (capt). Unused: E King, B Sparks, G Boulton, S Reynolds.
REFEREE: D Rose (Eng).