The Blues scored five second half tries when hammering the Dragons last weekend, but the Ospreys put them in their place with a dominant display that has moved them to the top of the Magners League.
Nikki Walker scored two of his side's three tries, Wales captain Ryan Jones also broke through for a try and man-of-the-match Dan Biggar completed an impressive individual display with an 11-point kicking haul.
The only missing ingredient was the lack of a try-scoring bonus point. Cardiff were 'nilled' for the first time in three years but Ospreys boss Sean Holley will have been frustrated at missing out on a fourth try.
Holley had Lions duo Adam Jones and Lee Byrne back in the starting line-up and after a bright start from the visitors, the Ospreys took the lead on 11 minutes with a smartly-struck drop goal from Biggar.
The Blues had a chance to level with a penalty after a scrum offence but full-back Ben Blair pushed his place-kick wide of the right post.
And three minutes later Biggar was also off target with a long range penalty effort after Robin Sowden-Taylor had failed to retreat after a tackle.
But, on 19 minutes, the Ospreys extended their lead to 8-0 with an unconverted try for Walker in the left corner.
Blair had done well to field an Ospreys up-and-under but at the breakdown the home side turned over possession through Andrew Bishop on the 22. Ricky Januarie and Jonathan Thomas then linked before Walker was sent crashing over in the left corner.
With the snow falling heavily, Cardiff suffered another blow on the half-hour mark when Wales centre Tom Shanklin hobbled off with a knee injury and the Ospreys almost instantly scored their second try.
From a scrum Biggar scythed through a gap and from that moment the Blues defence was in disarray as the Ospreys backs put it through the hands before big winger Walker went over in the left corner again, making it 13-0 for half-time.
Cardiff had some decent possession and territory before James Jones blew for half-time, the best of their scoring chances coming when former Osprey Richard Mustoe was bundled into touch a metre out from the try-line.
The match continued to go the way of the Ospreys after the break. Biggar converted a penalty within the first two minutes, and two minutes later a Blair penalty attempt rebounded off the left post.
And another Blues penalty in easy kicking range was reversed when the away side were penalised for some over-vigorous rucking on Ryan Jones.
Matters got worse for the Blues when tighthead prop Gary Powell was yellow-carded after a collapsed scrum, and from the resulting offence Biggar slotted his second penalty success as the Ospreys pushed into a 19-0 lead.
As the Blues showed little signs of a response in their first defeat by a Welsh region this season, the home side collected try number three, a deserved score for the hard-working Jones.
The Ospreys took a quick free kick instead of opting for a scrum and spun the ball out to the corner where skipper Jones went over, with television match official Derek Bevan confirming the grounding. Biggar added the extras ahead of Powell's return from the sin-bin.
The fourth touchdown never came and Cardiff could muster little in Ospreys' territory too as defences ruled the roost during the final quarter.
A Richie Rees chip through could have caused problems for the Ospreys but full-back Byrne was alert to the danger and a number of unforced errors also blighted the Blues' attempts to get back into the game - most notably when Sam Norton-Knight kicked the ball dead after the visitors had been awarded a penalty and a chance to set up a lineout catch and drive.
Speaking afterwards, Blues boss Dai Young admitted: "I can take very little out of this game and we have to take it on the chin as we were beaten by a far better team on the day.
"The Ospreys had us under a stranglehold for most of the game and once they got into our half they looked threatening.
"We failed to handle them and because we didn't have any field position, we couldn't find any momentum and create anything ourselves."
Pleased with his side's display, Ospreys forwards coach Jonathan Humphreys said: "Local derbies, especially against the Blues, are usually hard-fought encounters and we are delighted we didn't concede any points as we have worked on our defence to play such a high quality side.
"We feel December and January are the defining months in our season, we have planned meticulously for it and we are pleased with our progress."
|Ospreys Score Card|
|Cardiff Blues Score Card|