The Ospreys started brightly and they were almost rewarded with the opening try just five minutes in after their pack had put the Blues under pressure on their own put-in. Cardiff's number eight Robin Copeland attempted to pick up at the back of the setpiece but was unable to go forward and Lloyd Williams' attempted clearance at the back of the ruck was charged down by George Stowers deep inside Cardiff's 22.

The big Samoan gathered the loose ball and the Ospreys patiently worked their way right to left, close to the line, but when skipper for the night Kahn Fotuali'i attacked the blindside he was bundled into touch by two defenders just a metre out.

Nevertheless it was the hosts who opened the scoring four minutes later, Matthew Morgan with three points after another powerful Ospreys scrum was rewarded with a penalty.

With 11 minutes on the clock the Ospreys stretched their lead with a well worked try from King, his first for the region. It was the big second row himself who was soaring high in the lineout to secure good ball for Fotuali'i 10m out, the scrum-half darting forward before offloading to Joe Bearman who was held up just short of the line. However King was on his shoulder and there was no stopping the North Walian as he went over for the score, Morgan adding the extras.

The home team were playing confidently, looking to keep the ball alive wherever possible, but Morgan spurned the opportunity to take the lead to 13 points, his penalty after Dafydd Hewitt was guilty of not releasing in the tackle drifting to the right of the sticks.

Morgan had better luck a couple of minutes later, putting it over from the 22m line close to the left hand touchline after the Blues were penalised for a side entry.

Cardiff hit back through a penalty from Ceri Sweeney on 25 minutes following a lengthy advantage for offside against Morgan, play called back by referee Leighton Hodges after Mike Paterson's charge to the line was halted just short.

A promising Ospreys attack came to a premature end when Morgan knocked on just inside the opposition 22, but their dominance at the scrum resulted in a penalty against Tau Filise, Morgan with a straightforward three points.

The Blues hit straight back through the boot of Sweeney two minutes before the break, meaning the hosts went in holding a 10 point lead.

HALF-TIME: OSPREYS 16 CARDIFF BLUES 6

As the temperature at the Liberty Stadium dropped the Ospreys warmed up their supporters with a great try within 80 seconds of the restart through Fussell, his third of the season. The Blues defence failed to deal with a Fotuali'i box-kick from a lineout on halfway, and with a knock-on advantage in their favour the men in black spun it wide to Ross Jones on the right wing and his little dink behind the defence bounced perfectly for the fullback with the magic red hat as he raced through to score, Morgan with the extras.

With Sweeney having already departed the action, Rhys Patchell then knocked over the Blues third penalty of the night after an Ospreys offence at the scrum, leaving them trailing by two converted tries 46 minutes in.

Minutes later Patchell knocked over a second penalty, this time from halfway, after the Ospreys had been reduced to 14 for 10 minutes following a second yellow card in consecutive games to Sam Lewis, this time for coming in from the side to steal the ball at a ruck.

As the visitors looked to take advantage of the extra man the Ospreys played sensible, tight rugby which ate up the minutes and saw them slowly working their way back upfield where they were rewarded with a penalty that saw Morgan bring up the hour by taking the score to 26-12 in his team's favour.

The Ospreys were defending well and that was perfectly illustrated by a long period of Blues possession that saw them going through phase after phase, moving the ball the width of the field and back again but unable to find a way through, eventually cough up possession on the hosts 10m line.

However, an Ian Gough knock-on in midfield almost proved the Ospreys undoing, Fotuali'I having to race back to gather on his own line under pressure, the ball eventually being cleared to touch by Ross Jones.

Having weathered the storm the Ospreys were able to take control of the game again in the final 10 minutes, and were buoyed by a numerical advantage after Josh Navidi was sent to the bin for killing the ball after a dazzling Eli Walker run up the left had brought the crowd to its feet.

Walker was then inches away from scoring as he looked to ground in the corner after man-of-the-match Fotuali'i had cleverly switched play down the blindside, the wing knocking on as he looked to get the ball out from underneath him, stretching to dab down.

The third try looked as though it was never going to come, but when it did was simplicity itself, Morgan putting the ball in the corner from a penalty and quick lineout ball seeing the Blues defence opening up for Allen to cross for his third try of the campaign. With just a minute remaining Morgan wasted no time on the conversion, drop kicking it over quickly as the Ospreys targeted an unlikely try bonus but there was to be no dramatic finale as they had to settle for the four points.