Wales' Capital Region led 8-3 at the interval in Newport thanks to an Aled Summerhill try and the boot of Gareth Anscombe.
The encounter remained tooth and nail at a red-hot Rodney Parade but Cardiff Blues displayed their quality as they struck for tries through Rey Lee-Lo and Tom James.
Lloyd Fairbrother gave the Dragons hope and when Andrew Brace awarded the home side a penalty try on 72 minutes, the Cardiff Blues faithful could be forgiven for some nerves.
But, despite late pressure from the home side, Danny Wilson's side held out for a win in the first of three festive derbies, as focus now turns to the New Year's Eve clash against Scarlets at Cardiff Arms Park.
The Blues made an assured start at a sold out Rodney Parade, securing the kick-off and exiting before Garyn Smith intercepted a Gavin Henson pass.
Smith was tackled man and ball but the Blues were soon awarded a penalty by Andre Brace which Anscombe pushed left.
Despite the miss the Blues continued to enjoy the majority of possession however it was all around the half-way line and the Dragons threatened on the counter.
The home side had their first opportunity for points on 10 minutes and Henson, one of seven former Cardiff Blues players in the Dragons squad, fired the ball into the corner.
Cardiff defended their potent driving maul well but when the ball was moved wide the hosts threatened.
Hallam Amos hit the outside and threated a kick through to the corner and although Aled Summerhill just about won the race, he lost the ball in the scramble and the Dragons were awarded a five-metre scrum.
From the ensuing scrum the Dragons won a succession of penalties, which eventually saw Brad Thyer sent to the sin-bin, with Gethin Jenkins called to action the set-piece just about held and after a strong defensive set, the Blues forced a turnover.
The Blues' front-row were dealt a further blow six minutes later when Jenkins departed for a HIA following a heavy collision in midfield.
That saw Kirby Myhill come on and scrums become uncontested for the remainder of Thyer's yellow card period.
It was now the Dragons that pressured and they hammered at Cardiff Blues' line but on each occasion they were driven back until a turnover was forced.
The Blues almost broke out shortly before the half-hour mark following another turnover at the breakdown.
Possession was moved to Anscombe on the blindside and he raced along the left before releasing Matthew Morgan.
The full-back had a clear run in ahead but the Dragons' covering defence of Amos and Ashton Hewitt had the angle and he opted to hack ahead.
Bernard Jackman's men were able to avert the danger but they were soon penalised and Anscombe made amends for the earlier miss as he scored the game's first points.
He was soon back at the tee and was agonisingly wide with a long-range target from the left but the Blues were now in the ascent and struck for a fine try, albeit in fortuitous circumstances on 37 minutes.
After stretching the hosts with a number of phases they attacked down the left and Rey Lee-Lo, who signed a new contract yesterday, released Owen Lane with an inside ball.
He bumped off Henson and although there was still plenty of Dragons defence he managed to release and offload, which deflected off Joe Davies, with Summerhill the quickest to ponce.
Anscombe was off target from the touchline and Henson slotted the Dragons first points just before the interval to make it 8-5 at the break.
The second-half got underway with a series of mistakes from Cardiff Blues but they regained their composure and earned a superb scrum penalty to relieve the pressure.
With conditions worsening, errors continued to litter the game but there were moments of inspiration both in attack and defence, with a thunderous Nick Williams hit typifying the Blues' effort.
And they got their reward on 51 minutes with a second try following a sustained period of pressure.
Lane put the Blues on the front foot as he hit a delayed Williams pass and almost broke clear.
They continued through the phases and it was another pass from the young scrum-half, which caught a pedestrian Henson flat-footed and put Lee-Lo into a gap. The Samoan international needed no second invite as he crossed for his second try of the season.
Anscombe added the extras to stretch the Blues' led to 12. Henson quickly had the opportunity to hit back but he fired wide and he was soon made to pay as Wilson's men claimed their third.
The try was created following a turnover in midfield and the quick wits of Lee-Lo, who moved the ball.
Anscombe fired a long pass to Matthew Morgan, who eased around Ashton Hewitt and found replacement wing Tom James in support.
James cut inside and although tackled short his momentum was enough to slide over in the greasy conditions. Anscombe was once again on target as he made it 22-3.
To their credit, and fired on by the lively home crowd, the Dragons never gave in and they were rewarded for their perseverance as Lloyd Fairbrother drove over from close range.
Henson slotted the conversion and minutes later the hosts set up a tense finale as they kicked to the corner and rumbled towards the line, eventually earning a penalty try.
That set up a nail-biting finale but Seb Davies claimed a crucial line-out in the final play to allow Anscombe to kick the ball dead.