Although Blues didn't actually perform horribly as such, Cardiff were far more ruthless and scored three times, through Nathaniel Mendez-Laing, Craig Bryson and Callum Paterson.BCFC
Although Blues didn't actually perform horribly as such, Cardiff were far more ruthless and scored three times, through Nathaniel Mendez-Laing, Craig Bryson and Callum Paterson.
There was seemingly no way back for Blues. But in the second-half they gave it their best shot and handed the title-chasers several uncomfortable moments.
Craig Gardner scored from a penalty and there was an incredible let-off for the Bluebirds when Michael Morrison was denied from point-blank range what seemed a certain goal.
Maxime Colin cracked a shot into the top corner in the fifth minute of added-time and although Blues had cut the deficit and showed plenty of heart and pride after the break - they had Cardiff wobbling for long spells - they left themselves just too much to do.
The task became difficult intially when Blues conceded in the 12th minute, to Mendez-Laing.
Blues were attempting to come out of defence from a corner, but Cardiff gained possession back untidly.
The ball was with Mendez-Laing wide on the left and he cut inside onto his right peg, near the angle of the Blues box.
He drilled a shot low and hard and it whizzed past a crowd of bodies and just inside the far post.
There had been nothing in the game until then and Blues had started reasonably OK.
Gardner tried to lift Blues and let rip with a 35-yard shot that swerved all over the place and caused problems for Neil Etheridge, who did well in the end to bat it away from goal.
Then Lukas Jutkiewicz got the better of Bruno Manga and held him off near the byline, and crossed; only a timely sliding interception at the front post from Sol Bamba stopped Sam Gallagher from turning it in.
Blues response to the goal continued to be encouraging and from a 21st minute burst down the right by Carl Jenkinson, Gallagher got free in between the centre-halves but couldn't quite connect with his header as the cross came over at speed.
But hope all but evaporated after Jenkinson got himself in a muddle defending a long clearance downfield by Etheridge to concede a corner, Cardiff's first, the ball bobbling off his shins and out.
From the kick, Paterson horribly miscued an attempt at the far post and it went straight back to the taker, who laid it off to Joe Bennett.
Bennett drilled the ball in towards the box, hard and low, and Bryson got a touch to divert it past David Stockdale.
Two straightforward goals inside an 11-minute spell - and yet Blues, as they did after the opener, gamely rallied again.
Morrison glanced just wide of the post from a second ball in from a corner, and then Jutkiewicz, with options to his left and right as Blues sprung clear, stuck a drive straight at the 'keeper from the edge of the area.
Blues continued to force corners - they had six in the half - and gain free-kicks in good areas, but Cardiff stood firm to repel what came their way.
And, in the third minute of added-time in the period, Blues went further behind, yet another poor goal to let in.
From a cross on the left Morrison couldn't quite flick it away and the ball carried on its path for Paterson to glance down and in.
Again, from more or less nowhere, Cardiff scored once more.
They had hardly ripped Blues to shreds but they were already out of sight, being able to maximise whatever openings or ball were engineered - unlike the visitors.
Even before the break came, Jota breezed in from the right and moved into the area only to fire over with a right-foot drive.
Half-time: Cardiff City 3 Blues 0
Blues replaced Jenkinson with Marc Roberts at the break, with the substitute lining-up at right-back in a straight swap.
And in the 54th minute they got a lifeline, thanks the award of a penalty at a corner. Bamba was adjudged to have been tugging shirts as Jota's delivery sailed over into the heart of the box.
Gardner stepped up to take the spot-kick and swept it low to the left, sidefooted, and although Etheridge got hands on it, he couldn't keep it out.
Soon after Cardiff were in uproar as Roberts seemed to catch Junior Hoilett as he was about to pull the trigger and shoot, from the left of the area. Roberts was behind Hoilett as he veered free into the box and checked across him - the referee waved play on.
The incident sparked the whole stadium, sent Neil Warnock into a rage and all of a sudden there was an extra competitive edge from both teams, with Blues not holding back.
In the 65th minute Blues went agonisingly close to scoring again, from a whipped in corner from the right by Jota.
Morrison steamed in behind everyone and got a strong sidefooter onto the ball but somehome, from four yards, it hit the diving figure of Etheridge - who knew nothing about it - and incredibly stayed out, spinning wide and away from the back post.
Morrison couldn't believe it and nor could the travelling fans, whose backing of the team throughout was yet again excellent. It was a massive let-off for Cardiff, who had become more and more rattled by Blues bite and performance after the break.
Che Adams replaced Jutkiewicz, who had put in another sterling display, and Blues maintained their belief that they could salvage something.
Cardiff themselves brought on Sean Morrison to try and stiffen things up and lead as captain from the heart of the defence and shifted Manga out to right-back - a sign of how Blues had been making all the running.
Adams surged down the left on a swift counter by Blues to take Jacques Maghoma's pass, in the area, and he fired on the run not too far wide of the post.
Once more Blues served notice that they were still in it and Cardiff made another defensive change, bringing on Greg Halford for Mendez-Laing with 10 minutes to go.
Jota moved into a more central role from the right to try and help conjure things and Cardiff had opportunities to kill Blues off as space opened up, but Blues showed resolve when they had to.
Hoilett, clean through in the 90th minute, should have scored a fourth but with Roberts breathing down his neck somehow rolled the ball wide of the post, and with Kenneth Zohore waiting alongside for a tap-in.
Blues showed, as the fans sang, they they fight to the end by scoring a second goal.
Gardner spread the play out to the left and Jeremie Boga and Colin combined to get the Cardiff defence in a twist.
The ball broke to Colin, on the charge, and he cracked a powerful shot that ripped into the top corner, with the aid of a deflection on the way.
Unfortunately it was so late - the fifth minute of added-time - that the final whistle blew moments later, but not after a Roberts long throw in the area caused Cardiff a nail-biting last piece of action.
Cardiff (4-3-3): Etheridge, Peltier (Morrison 73), Bennett, Manga, Bamba, Paterson, Grujic, Bryson (Damour 36), Hoilett, Zohore, Mendez-Laing (Halford 80).
Substitutes not used: Murphy, Pilkington, Wildschut, Madine.
Goals: Mendez-Laing (12), Bryson (23), Paterson (45+3).
Bookings: Bamba (58), Etheridge (78).
Blues (4-4-2): Stockdale, Jenkinson (Roberts ht), Colin, Dean, Morrison, Jota, Kieftenbeld, Gardner, Maghoma (Boga 79), Gallagher, Jutkiewicz (Adams 69). Substitutes not used: Kuszczak, Ndoye, Bramall, Lowe.
Goals: Gardner (pen, 54), Colin (90+5).
Bookings: Dean (68), Morrison (88).
Referee: P Bankes.