The Blues had an early chance to open their account, an Ospreys offside allowing Leigh Halfpenny to go for goal from a metre inside the visitors half, and the Wales fullback made no mistake as he slotted it over with the help of the left upright inside two minutes.

Biggar levelled things six minutes later with a penalty of his own from 40m out after Blues centre Gavin Evans had prevented Andrew Bishop's pass finding Joe Bearman as the Ospreys looked to work an overlap, his outstretched arm knocking the ball down to the floor - resulting in a yellow card from referee George Clancy for a deliberate knock-on.

Martyn Williams was then pinged for not rolling away after his tackle on Richard Hibbard, but on this occasion Biggar's radar was off, his kick going just a metre or so wide to the left.

The Ospreys were on top with the numerical advantage and a powerful charge from Ryan Jones, collecting the ball on halfway and running straight at the Blues defence, caused concern for the hosts. Shane Williams carried well before the ball was eventually worked back to Ryan who was held up a metre short. The forwards recycled, Alun Wyn Jones went for the line and when the ball squirmed out on the Blues side the decision was penalty for hands in the ruck. Given their position close to the line the Ospreys opted for the scrum only for Mr Clancy to penalise the visitors as the two packs went down.

With the Blues back up to 15, Halfpenny was able to dance his way through a number of tackles before the first match-up between Alex Cuthbert and Shane Williams on the wing, the veteran Osprey coming out on top after valiantly clinging onto the Blues youngster as he looked to force his way through.

As the Blues applied pressure on the Ospreys line for the first time, an offside call allowed Halfpenny his second shot at goal and he made no mistake, putting his side 6-3 ahead with 24 minutes gone.

The Blues survived a scare when Luke Hamilton's wayward pass in his own 22 put his side under pressure, Andrew Bishop hacking the loose ball towards the line, but the centre was unable to finish it off, claiming he was impeded as he chased the kick.

A huge shove from the Ospreys at a Blues put-in close to halfway saw the home eight disintegrate, allowing Biggar to level things once again, but Halfpenny nudged his team back in front just 90 seconds later, Ryan Jones caught in front of Kahn Fotuali'i as the Samoan scrum-half looked to clear.

Neither side had been able to truly put their stamp on what was a low-key opening 40, but Halfpenny was able to double his side's lead a minute before the break after Richard Fussell was pinged for holding on to the ball after finding himself isolated.

HALF-TIME: CARDIFF BLUES 12 OSPREYS 6

The opening minutes of the second half continued in the same pattern as the first, stop-start, with the referee's whistle all too often preventing any real rhythm developing.

Shane Williams showed good awareness to sweep up the danger after Ceri Sweeney had charged down a Biggar kick on halfway, the winger getting across well to bundle Sweeney into touch as he looked set to race clear.

Slowly though, the Ospreys began to get on top and they showed great patience to go through 18 phases as they inched their way closer to the line. It looked as though they were going to get their reward when Joe Bearman eventually punched a hole in the Blues defence 5m out, but Sweeney's tackle prevented a clean offload and Fotuali'i knocked on as he looked to pick up off his bootlaces.

At the resulting scrum another huge Ospreys shove saw the setpiece go through 180 degrees, with a penalty going the Ospreys way at the second attempt. Unsurprisingly, the Ospreys opted to go for the scrum again, just 5m from the line, but this time, as Bearman marched the ball towards the line Mr Clancey whistled, awarding the scrum in the Blues favour claiming the Ospreys front row had wheeled it, to their obvious annoyance.

On this occasion, the Blues just managed to keep their line intact, the ball squirming out and the Ospreys penalised for offside as they looked to pounce on the loose ball.

Although the Blues were able to clear into touch, they played themselves back under pressure, slow ball from the lineout allowing Hibbard to charge down Lloyd Williams attempted clearance, the hooker then securing the loose ball. As the Ospreys looked to move the ball, Sweeney stepped in to intercept Alun Wyn Jones' pass but failed to gather, the referee adjudging it to be a deliberate knock-on and sending the fly-half to the bin. Biggar was left with a simple kick, reducing the deficit to three points.

The Ospreys again made a complete mess of the Blues scrum, winning another penalty on their opponents put in as Justin Tipuric made a nuisance of himself, Biggar levelling things just before the hour.

It was delicately poised, but the Ospreys grabbed the first try of the night on the hour mark, through skipper Alun Wyn Jones. He received the ball 20m out from replacement nine Rhys Webb and his sidestep past Martyn Williams saw him scything through the Blues defence. With the path to the line opening up, Halfpenny was left clutching air, and although Dafydd Hewitt brought him down, the big lock was able to reach out and ground the ball, putting his team in front for the first time, Biggar converting to take the Ospreys seven points clear at 19-12.

It was one way traffic now such was the Ospreys dominance and the second try dully arrived in the 68^th minute. The initial break came from Tipuric after the Blues had failed to deal with Fussell's up and under, but after going through several phases, it was the unlikely figure of Adam Jones who found himself bursting through the Blues defence and there was no stopping him from close range. Biggar again added the extras, taking the Ospreys 14 clear.

With the Ospreys well in the ascendancy as the clock ticked down it came as no surprise when they added a third try at the death, the forwards rumbling forward from a scrum 10m out and Tom Smith dabbing down. Biggar's conversion made it 27 unanswered points after the break as the Ospreys secured a valuable win.