Three tries and the boot of Jarrod Evans were enough for Cardiff to secure a 12th consecutive United Rugby Championship victory over the Dragons despite playing the majority of the second half with 14 men.
Lloyd Williams and Hallam Amos crossed for tries in the first half of a fiery Welsh derby at the Arms Park and the Blue and Blacks led by four at the break.
The impressive pack earned a powerful penalty try early in the second-half before Rey Lee-Lo was shown red. However, Evans kept the hosts out of reach with penalties which included a stunning 50 meter effort.
The win ties sees Cardiff closing the opening block of URC fixtures with three wins under their belts, with a trip to South Africa next on the menu for Dai Young's men.
It was a nightmarish start for Cardiff as the kick-off was not secured and the Dragons were awarded the scrum.
They were driven back by an aggressive pack but managed to retain possession and began to carry with real venom. Everything the Dragons did was with pace and intensity and following a sustained period of pressure and a neat offload that forced Matthew Morgan into a last ditch tackle the damage was done.
The ball was quickly recycled and Taylor Davies dived over with Sam Davies converting to give his side a 7-0 lead inside three minutes.
Cardiff soon hit back through the boot of Jarrod Evans but they were dealt another blow just before the 10 minute mark when his half-back partner Lloyd Williams was sent to the sin-bin.
The scrum-half had made a covering tackle but through no fault of his own he caught Jordan Williams high as he was brought down from the other side.
Dean Ryan’s men added a second try while Williams was in the bin and it was more of the same from the Dragons who played with real ferocity. Cardiff defended wave after wave of attack but e eventually ran out of numbers as Message Doge crashed over from close range.
The try sent the visiting support into euphoric celebrations but Cardiff slowly worked their way back into the game and it was a case of villain to hero as Williams made amends with the hosts’ first score.
It came from the first sustained period of Cardiff pressure and while they struggled to to break through the Dragons defence, Williams spotted a gap at the breakdown and darted through unopposed.
He was caught as he stretched for the line but maintained control for just long enough to touch down on the line. Evans added the extras to make it a one score game.
Minutes later, Cardiff almost claimed a second quick-fire try in stunning fashion following some fine defensive play from Josh Turnbull. The home captain stripped the ball out of contact on the 22 and popped the bobbling ball to Morgan who embarked on the counter.
He combined with Evans to release Amos down the left. He pinned his ears back after sending a dummy and as he was caught in the corner he threw an inside offload but it found Dragons hands instead of Evans.
The Blue and Blacks did go into the break with the head however with Amos needing no second invite to score. It was more clever play from Williams who spotted space behind and dinked a perfectly weighted chip over the Dragons rush defence.
It sat up perfectly for Amos, who collected to score against his former team just days after announcing he will retire at the end of the season.
Evans conversion drifted agonisingly to the right of the uprights but the score had given his side a 18-14 half-time lead.
Defence alarm bells were left ringing shortly after the restart after Matthew Morgan was taken out in the air and Ben Whitehouse waved play on to the dismay of the home crowd.
The Dragons claimed the loose ball and went on the attack, eventually moving play to the right corner where Ben Fry powered over. Fortunately the incensed crowd and TMO Sean Brickell ensured the referee consulted video replays and the try was chalked off.
It was undoubtedly the correct decision and swung momentum back in Cardiff’s favour and they quickly capitalised.
After a sustained period of pressure they kicked a penalty to the right corner and unleashed a rampaging driving line out, which blew the Dragons defence apart and forced a penalty try.
The score gave Cardiff breathing space with an 11-point lead but they were soon left with nerves in tatters after the red card.
Lee-Lo went upright into a tackle and while Sam Davies did dip slightly into contact there could be few complaints as he was given his marching orders.
Buoyed by their one-man advantage, the Dragons began to attack in the wider channels but they were frustrated by a pair of Evans penalties, the second from the half-way line.
Those penalties booted Cardiff into a 31-17 lead but they still faced a big task following the disruption of three first half injuries and the red card.
They got the try they were searching for on the hour mark as Rio Dyer coasted over in the corner but Davies failed to add the conversion and Cardiff clung onto a nine point lead.
With plenty of to play for in the final 10, both sides had their opportunities and it was Dragons who had the last word, snatching two bonus points in the final play as Joe Maksymiw powered over.