The Ospreys scored four tries as they recorded a fourth win in five matches across the PRO14 and Europe, but it was too close for comfort as the visitors scored two late tries to give them a fright.
With a bonus point in the bag and the Ospreys leading by 15 inside the final quarter it seemed like game over, so Steve Tandy’s team will be mightily relieved to hear the final whistle go.
On a cold and crisp afternoon at the Liberty Stadium it was the visitors who had their noses in front with barely a minute played, Gareth Anscombe with the simplest of three points from in front of the posts.
There was a positive response from the Ospreys, looking to move the ball, but sloppiness at key early moments saw good possession being lost on more than one occasion.
It took 16 minutes for either side to carve open a real opportunity, the Blues using a scrum on the left, 10m inside the Ospreys half, as a platform to launch a set play, Rey Lee-Lo breaking Dan Evans’ tackle before pinning his ears back and going for the corner, only for Jeff Hassler to get across to his opposite wing and halt his progress.
The respite was only temporary as seconds later, from a lineout, Nick Williams was able to power over from close range. Anscombe missed the conversion, but his team led by eight.
Hassler was at the heart of the action at the other end minutes later when he helped himself to the Ospreys’ first try, reading Matthew Morgan’s outside pass after he had collected Rhys Webb’s kick, the Canadian intercepting on halfway and racing upfield to score, Biggar adding the extras.
A failure to clear their lines from the restart handed Anscombe another straightforward three points, but within two minutes the Ospreys led for the first time after some magic from the half-backs
Biggar was the catalyst with a lovely chip and chase over the defensive line and his pick up and pass in one movement freed Webb to race clear, Biggar adding two to take the scoreboard to 14-11.
It was all square just after the half hour, over eager defenders straying offside to hand Anscombe another shot of a goal from a central position 40m out and he made no mistake.
The Ospreys were ahead again inside three minutes, Biggar with the kick after some good work at the breakdown to win the penalty and they held that lead at half-time.
HALF-TIME: OSPREYS 17-14 CARDIFF BLUES
The hosts were on top after the restart, controlling the game, and try number three came on 50 minutes – and what a beauty it was.
Biggar sparked the move with a perfectly weighted cross kick for Ashley Beck. The centre read it well, stepped infield and fed Justin Tipuric. He kept the ball moving, slipping it to Webb 20m out and, with plenty to do, the scrum half sidestepped his way past the cover to score his second of the match.
The conversion was good, once again, and the Ospreys led by 10 points with a little under half an hour to play.
The Ospreys came agonisingly close to a fourth try on 57 minutes, the forwards driving from a lineout, Tipuric held up over the line.
As the home team pressed, the penalty count against the Blues was rising and, eventually, Alex Cuthbert was shown yellow for a deliberate knock-on close to his line. The Ospreys took full advantage, the bonus point try arriving within seconds.
With Biggar holding the ball in hand on the left wing everybody at the Liberty was expecting him to go to the corner but he spotted Tipuric in acres of space hugging the opposite touchline and punted it across field to give the flanker the easiest of scores.
For once Biggar was unable to add the extras but the Ospreys now led 29-14.
Having been on the defensive for almost the entirety of the second half to this point the Blues were finally able to gain some territory and it didn’t take them long to grab their second try.
It almost came on the left, Nick Williams trying to get Owen Lane free, the winger held up just short. However, it was recycled and, just 30 seconds or so later, it was Lane who burrowed over on the opposite side of the field. Anscombe slotted the conversion and, with nine minutes remaining, the deficit was eight points.
It was squeaky bum time when Alex Cuthbert then set up Garyn Smith with five minutes remaining, Anscombe cutting the deficit to a solitary point.
The Ospreys looked to squeeze the life out of the game, spurning a kickable penalty with 90 seconds on the clock but an overthrown lineout handed the Blues one last chance to go from their own line. However, it was a big ask, the Ospreys eventually winning a penalty on halfway to bring the game to a close.