Full-time: Cardiff Blues 31-30 Gloucester
Late Anscombe penalty gives Cardiff incredible win
Tomos Williams, Garyn Smith & Scully cross for Blues after break
Trinder & Atkinson score fine tries for Gloucester in first half
Hanson adds third try for Premiership side
Gloucester led 20-6 at half-time
Cardiff Blues 23-30 Gloucester
With 15 minutes to go Gloucester have very much got their mojo back.
They look really good right now, but Cardiff are just one moment of magic away from making it all-square.
Image source, Getty ImagesCardiff Blues 23-30 Gloucester
49m out. On the angle. No problem for Billy Twelevetrees. He extends Gloucester's lead from the tee.
Nailbiter.
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Andrew Priestley: What a tackle from Lewis Ludlow, timed to absolute perfection.
Image source, Rex FeaturesCardiff Blues 23-27 Gloucester
Gloucester replace the entire front row, so John Afoa's career in cherry and white is over.
And what a tackle by Lewis Ludlow on Gareth Anscombe as the Welsh full-back takes a high ball - one of those ones that will have knocked every filling out of the Welshman's teeth.
It's the sort of hit that can change the momentum of the game. Ouch!
Cardiff Blues 23-27 Gloucester
Image source, Rex FeaturesJames Hanson dives over from the Gloucester maul after the close line-out. Relief for Gloucester as they re-take the lead, but what a second half we have had.
Billy Twelvetrees adds the conversion
It really is anybody's final.
Image source, Rex FeaturesCardiff Blues 23-20 Gloucester
Gloucester win a line-out on the Cardiff 5m line. Here comes the shove...
Cardiff Blues 23-20 Gloucester
Cardiff Blues have turned this game on its head in 15 second-half minutes!
Garyn Smith goes over, despite looking like he was offside, after a lovely chipped kick through.
Jarrod Evans adds the extras.
Cardiff 16-20 Gloucester
Gloucester see Jeremy Thrush - the former All Black - come on while Mariano Galarza has a head injury assessment.
Can the experienced Kiwi get Gloucester back on track here?
Cardiff 16-20 Gloucester
Gloucester rip the ball away illegally according to referee Jerome Garces. Perhaps another harsh one?
Either way Jarrod Evans makes no mistake, four from four from the tee and the gap is down to four points.
Cardiff Blues 13-20 Gloucester
Dafydd Pritchard
BBC Sport Wales in Bilbao
You'd think Lloyd Williams would be the undisputed owner of the title of 'Best Left-footed Footballer Playing Scrum-half for Cardiff Blues' after his kick ahead set up Gareth Davies' match-winning try for Wales against England at the 2015 World Cup.
But Tomos Williams may just have pipped him to that niche accolade with that fabulous score.
Image source, Rex FeaturesCardiff Blues 13-20 Gloucester
Cardiff are going at Gloucester now, it's a really dangerous period for the English side. Another Blues score here and they really are back in this one.
Incidentally, in all that early madness, I forgot to tell you that it's 255 games and out for Taufa'ao Filise for Cardiff.
The prop ends his career after a half in Bilbao and is replaced by Scott Andrews.
Cardiff Blues 13-20 Gloucester
Image source, Getty ImagesWhat a start from the Blues!!! A wonderful chip through from Gareth Anscombe releases Tomos Williams who beats Callum Braley in a footrace, kicks the ball against the post, gathers it and goes over under the sticks.
Jarrod Evans gets the extras.
Cardiff Blues 6-20 Gloucester
We are back under way. Can Cardiff carry out the biggest comeback in Challenge Cup final history?
HT: Cardiff Blues 6-20 Gloucester
Can Cardiff find a way back into this game and if so how?
Will Gloucester carry on and avenge last year's loss in the final with victory in 2018?
Let us know using #bbcrugby on Twitter. Meanwhile, the teams will be making their way back out for the second half in Bilbao in a matter of moments...
Image source, Rex FeaturesHT: Cardiff Blues 6-20 Gloucester
Can Leinster win a record-equaling fourth European title on Saturday?
The Dublin-based province take on French giants Racing 92 in the Champions Cup final in Bilbao on Saturday at 16:45 BST.
The Irish side will go level with Toulouse for the most amount of titles won if they can get past a Parisian side who are able to leave New Zealand legend Dan Carter on the bench.
We will have live text commentary on the game here on the BBC Sport website and app, while BBC Radio 5 live will also broadcast the match.
Image source, Getty ImagesCardiff Blues 6-20 Gloucester
Dafydd Pritchard
BBC Sport Wales in Bilbao
That was an impressive end to the half from Gloucester, who look to be in control now.
Cardiff Blues have looked off the pace, struggling to regain their composure after losing Navidi and Lane to injury.
They've got a huge task on their hands if they are to turn this around.
Image source, Rex FeaturesCardiff Blues 6-20 Gloucester
So those 10 quick points at the end of the half for Gloucester give both sides a new perspective for their half-time team talk.
Cardiff have to get something going in attack, while you feel Gloucester could be like the rugby version of an anaconda coiling themselves around Blues and gradually suffocating them.
Cardiff Blues 6-20 Gloucester
Ellis Jenkins is penalised for going in off his feet - looked a bit harsh from here.
Billy Twelvetrees sticks it over from 40-odd metres to end the half leading by 14 points.
Cardiff Blues 6-17 Gloucester
Image source, Rex FeaturesA wonderful bit of play by Gloucester ends with Mark Atkinson going over.
It's really clever play by Billy Twelvetrees to evade a challenge and get the move going. He feeds Callum Braley who times his pass out to Atkinson to perfection and the speedster coasts over.
Twelvetrees adds the conversion.
Cardiff Blues 6-10 Gloucester
Now the Blues have some possession - but Gloucester's defence are doing really well to stifle the Welshmen and in the end they lose possession after a forward pass.