It was scoreless at the interval, despite the home side dominating both possession and territory in a one-sided opening 40.
Half time saw the pre-planned substitutions of Gethin Jenkins and Gareth Anscombe, who continued their rehabilitation process, but second half tries by Reuben Morgan-Williams and Rhys Williams sealed the victory for the Swansea-based region.
Harri Millard gave his side late hope of a comeback, but the reliable boot of replacement Sam Davies gave the visitors the edge, sealing the victory.
The home side enjoyed the majority of the early possession, and were almost gifted the first score of the evening with a matter of minutes on the clock.
Owen Lane looked to win the race to a loose ball deep inside the Ospreys’ 22, but opposite number, Tom Williams, was on hand to safely touch down for a drop-out.
The visitors were dealt an early blow when lock Rory Thornton was forced off with an injury, and was replaced by former Cardiff Blues player, Bradley Davies.
With 15 minutes on the clock, the deadlock as yet to be broken, but an Ospreys penalty gave James Hook an opportunity to bring play into the Cardiff Blues 22.
Richard Hodges’ side defended the resulting driving line-out well, and following numerous phases around the 5m line, referee Adam Leal awarded the home side a penalty and a chance for Steven Shingler to relieve the pressure.
The hosts remained patient with their possession, but Ospreys’ defence proved difficult to break down.
Lane was released down the right and offloaded to Harri Millard in support. The wing couldn’t keep his hands on the pass, but managed to gather before the ball hit the ground.
Will Jones put a good hit on Millard, but the Blues’ attack continued and were awarded a penalty.
Shingler found touch in the corner, and following a number of phases and stubborn defensive effort from Ospreys, the home side were awarded another penalty, with Leal warning the visiting captain, Luke Price.
Anscombe this time dinked to the corner, and once again Cardiff Blues were camped inside their opponents’ 22, but a turnover on the tryline allowed Morgan-Williams to clear the lines.
It remained scoreless going into the interval, and pre-planned half time changes saw youngsters Rhys Carre and Ben Thomas replace Gethin Jenkins and Gareth Anscombe, respectively.
It only took four minutes of the second half for the visitors to open the scoring. Hook gathered a loose Rhun Williams kick, and chipped over the Blues’ chase line.
The chip fell perfectly for Price, and Ospreys worked it through the hands to scrum half Morgan-Williams, who raced away for a score.
Price converted, but the home side replied instantly, with Shingler putting three points on the board, after an Ospreys infringement at the scrum.
There was a long break in play as Kieran Williams was stretchered off, but play restarted with an Ospreys penalty, which Davies converted to restore his side’s seven-point advantage.
Tom James showed signs of his attacking threat, and a half-break gave his side a platform to attack, resulting in another penalty, which Shingler slotted to close the gap.
Shingler added his third penalty of the evening as play edged into the final quarter, with Rob McCusker sent to the sin bin, before Tom Smith’s side added another three points from the boot of Welsh international Davies.
A long-range penalty effort was out of Davies’ range, as he failed to stretch his side’s lead, but the disappointment would be short-lived as a turn-over in midfield allowed the visitors to attack down the left.
Will Jones powered his way through and found the support run of Rhys Williams on his inside, who slid in, despite the efforts of tracking defender, Sion Bennett.
Davies kept the scoreboard ticking for his side, but Millard broke free of the defence to give his side a glimer of hope of a stunning comeback.
However, having failed to gather the restart, the home side were penalised and Sam Davies stepped up to seal his side a 10-point victory.