An Owen Lane hat-trick was not enough as Cardiff Blues paid the price for a lacklustre first half against Pau in the European Challenge Cup.
Lane gave his side the perfect start in Pyrenees but Pau soon took control of the encounter as they wrapped up the bonus-point inside the first-half and led 24-7 at the break.
They soon claimed a fifth try to take their lead to 24-points and it appeared ominous for the Blues but they had other thoughts.
A Hallam Amos try sparked the comeback and in the space of eight minutes Lane added two more with Jason Tovey keeping the scoreboard ticking to take Cardiff Blues within five points.
An emphatic comeback was well and truly on before Pau slotted a penalty to take them out of reach despite Wales’ Capital Region’s desperate efforts.
They fought to the death and salvaged a second bonus-point thanks to a Tovey penalty at the death.
Cardiff Blues remain in second place in Pool Five, sitting three points ahead of Pau with Leicester Tigers away and clear.
Following last week’s bonus-point victory over the same opposition, Cardiff Blues knew another win would go a long way towards securing a quarter-final place.
They made the perfect start as Lane snatched a try inside four minutes. It had been all Pau in the opening minutes but when Josh Turnbull collected a high box-kick all it took was one simple pass to put Lane away.
The wing was happy to oblige, and he crashed over with Evans converting with the help of the left upright for an early 7-0 lead.
However, from here on in it was one-way traffic as Pau, reinforced by several first team regulars and a debut for All Black legend Ben Smith, flexed their forward muscle.
Cardiff Blues were struggling to cope with the monster French pack who continually piled on the pressure whether putting the squeeze through the set-piece or carrying with vicious intent.
It was their gargantuan scrum that laid the foundations for their first try as they won a penalty and kicked to the corner. The Blues soon conceded another penalty and Thibault Daubanga took a quick tap. The damage was done and Mohamed Boughanmi soon powered over for his side’s opener.
Four minutes later Pau claimed their second try, once again courtesty of their pack who powered over for a simple driving lineout after winning a scrappy penalty in midfield.
Former All Black Tom Taylor failed to add the extras but the try had ensured the hosts were now in control with a 12-7 lead.
Cardiff Blues did their best to stay in the encounter, fighting for every scrap with Matthew Morgan in particular causing the hosts problems with some intelligent kicks to the corner but Pau soon dealt a devastating blow.
It came from bizarre circumstances as the ball switched between the two teams in a scrappy, error-strewn spell on half-way until Smith, making his debut for the club, popped out of a ruck and raced clear drawing Morgan and putting Pierre Nueno away.
Taylor added the extras and once again the hosts struck twice in fast succession. With the clock approaching half-time approaching they once again worked their way deep into Welsh territory and their pack turned the screw at scrum time.
The Blues clung on but Pau then went through the backs and a pinpoint grubber to the corner saw Pourailly spectacularly dive over for the bonus-point try.
Taylor was unable to convert but the try had given his side a 24-7 lead at the interval and it took them just five minutes after the restart to claim their fifth with Baptiste Pesento the scorer.
The Blues appeared down and out with Pau now 31-7 up but they soon rallied with Pau’s monster pack running out of steam.
Following a sustained period of pressure, which involved a number of scuffles and a two Pau yellow cards for cynical infringements.
With Pau now reduced to 13 men, Jason Tovey kicked a penalty to the corner and while they were unable to rumble over the ball was spread left and the French club ran out of numbers as Amos ran in for his first try in Cardiff Blues colours .
Tovey was unable to bisect the posts but four minutes later he was back at the tee. It was a stunning effort from deep from Wales Capital Region as the ball was spread to the left with quick hands.
Morgan released Amos who tore into the Pau half before finding Lloyd Williams in support on the inside. The scrum-half probably could have made it but released Lane, who cantered in for his second of the afternoon with Tovey now on target.
With the score 31-19, Cardiff Blues were now well and truly back in the contest and their stunning comeback continued four minutes later as Lane completed his hat-trick.
The Blues were running the ball from all angles and quick hands from Liam Belcher gave Morgan a sniff of space. He dinked a delicate grubber through for Lane, who stepped inside one man before gassing the French cover defence and running over the sticks.
Tovey was again on target but a late penalty from Clovis Le Bail put the final nail in Cardiff Blues coffin as they trailed by eight points with less than five minutes to go.
However, Tovey was back at the tee in the final moments, as his penalty ensured Cardiff Blues would leave France with two points in the bag.