Following last weekend’s 28-3 victory over Bath at BT Sport Cardiff Arms Park, the Blues went into the encounter with confidence and momentum.
They trailed just 10-3 at half-time with Bath’s Ross Batty claiming the only try but two isolated incidents of indiscipline proved costly.
In a matter of minutes the Blues lost Kirby Myhill to the sin-bin and then George Earle to a red card.
And Bath showed no mercy as Jack Wilson, Aled Brew, Elliott Stooke and Batty crossed the whitewash for tries.
Bath are now level on points with Danny Wilson’s men but top Pool Four thanks to their superior head-to-head match points.
Bath dominated the opening 10 minutes in terms of possession and put the Blues on the back foot with some clever kicks to the corner.
With speed of ball they were stretching the Blues and it looked like their pressure had eventually taken its toll on 14 minutes.
They quickly moved the ball to the left and Jonathan Joseph released Taulupe Faletau on the wing. He rampaged along the touchline but Matthew Morgan did enough before Willis Halaholo completed the job.
Bath maintained possession and went through a succession of phases before Batty knocked on in midfield.
The Blues won the ensuing scrum but were unable to get out of their twenty-two and were soon penalised, allowing George Ford the opportunity to open the scoring but he skewed the simple penalty wide.
They finally found their way into Bath territory thanks to a fine Halaholo kick and soon opened the scoring after Max Lahiff failed to roll away at the breakdown.
But Bath came back and a well-placed Ford chip laid the foundations, with Ben Tapuai collecting. He targeted Morgan but the full-back defended superbly and the ball was knocked on.
However, the hosts were now deep in Cardiff Blues territory and their sustained attacks eventually paid dividends with Batty slicing through and Ford converting.
The England fly-half kept the scoreboard ticking to bring the scores to 10-3 but the Blues rallied in the final stages of the half with Macauley Cook making major inroads with a rampaging break.
Possession was maintained with both Lee-Lo and Halaholo going close. A stunning sleight of hand from Cory Allen put Shingler over in the corner but the ball was dislodged by the covering defence.
Referee Alexandre Ruiz came back to award the Blues a penalty but Shingler struck the upright and the scores remained 10-3 at the interval.
They returned for the second-half without Blaine Scully, who came off for Nicky Robinson just before the interval following a heavy clash of heads. Robinson came on at 10, with the rest of the back-line shifting out. Scott Andrews also came on for Taufa’ao Filise.
The Blues suffered a set-back when Myhill has sin-binned for a dangerous tackle with Bath taking advantage almost immediately with Jack Wilson squeezing into the corner.
And they were dealt a monumental blow as TMO replays showed George Earle make contact with the eye area of Tom Ellis, resulting in a red card before Ford converted.
Wilson’s men rallied manfully and piled on the pressure with a serious of five-metre scrums following a Lloyd Williams kick through.
Ruiz award two consecutive penalties but then pinged the Blues to allow Bath to clear their lines.
They soon claimed a third try with Kahn Fotuali’I floating a long, and what appeared forward pass, for Brew to dive over. Following a succession of replays the score was eventually awarded and Ford added the extras to make it 24-3.
Again the Blues rallied but Batty intercepted a Robinson pass and galloped in for his second try after tireless Navidi slipped and took out Robinson in the process.
Bath added a fifth try in the final play of the game, as Rey Lee-Lo was closed down inside his own 22m. Bath forced the turnover and Stooke was on hand for an easy run-in.