Danny Wilson’s side trailed by as much as 11-points after the visitors twice struck against the play with some fine finishing following Adam Warren’s opener.
Kristian Dacey’s 20th Cardiff Blues try kept his side in touch at half-time and following a long period of pressure with little reward, they turned on the style with five second-half tries – much to the relief of a bumper crowd.
Tom James, Alex Cuthbert and Jarrod Evans all crossed in between a Matthew Morgan brace as the Blues kick-started their PRO14 season as attentions turn to Europe.
There was plenty of drama inside the opening minutes as the Dragons raced into a seven-point lead.
The Blues had been in the ascent but after the ball was coughed up the visitors struck.
Taufa’ao Fillise caught Hallam Amos with a high tackle but possession was maintained superbly and Henson completed the counter-attack with slick hands to put Adam Warren over.
Filise was duly shown yellow and despite television replays that suggested a forward pass, referee Nigel Owens adjudged it to be flat and awarded the score.
Henson bisected the posts but the capital region responded in perfect vein and pulled the Dragons from left to right.
Despite some desperate defence, the pressure eventually told as Dacey forced his way over from close range and Evans converted from the right touch line.
But the fast-paced, and often frenetic, nature of the game continued as the fired-up Dragons roared back with Henson pulling the strings.
The former Cardiff Blues star showed several classy touches as the Dragons went on the attack and he made the scoring pass as Elliott Dee bumped off Keiron Assiratti in the corner.
Henson was once again on target as he brought the scores to 14-7 to the visitors after just 10 minutes.
Despite a series of marginal decisions, and off the ball contacts, all going the way of the Dragons, the Blues continued to battle but they were unable to find the final scoring pass.
Their endeavour eventually paid off as Evans slotted a penalty following pressure at the scrum, however the hard work was undone as the Dragons struck against the run of play on 32 minutes.
Cardiff Blues had been forcing the Dragons into mistakes and a series of loose passes saw them on the back-foot but when the ball bounced to Tyler Morgan fortuitously, the defence opened.
Morgan showed superb pace to take advantage of the three on two and after tearing into the home 22, he sent George Gasson over the whitewash.
Henson maintained his 100 per cent strike rate to open up an 11-point advantage with less than 10 minutes of the half to play and despite plenty of pressure in the closing stages the Blues were unable to cut the deficit.
Wilson’s side were immediately on the attack in the second half and Seb Davies going agonisingly close before finding Cuthbert with an outrageous offload but he was also held short.
The Dragons survived but the home side set up camp in the red zone and on 44 minutes Morgan scampered over with Evans adding the extras.
Bernard Jackman’s side instantly hit-back after the Blues failed to secure the restart and were then penalised at the breakdown.
However, they continued to threaten with Rey Lee-Lo and Seb Davies rampaging in attack but they failed to finish a number of opportunities with Damian Welch losing the ball with try-line at his mercy and a pair of overlaps squandered.
A try appeared inevitable minutes later as Willis Halaholo powered through the Gwent defence and then found Olly Robinson but the home side were then harshly penalised at the breakdown.
With the Dragons on the racks and Cardiff Blues desperate to find a vital score the encounter descended into a major bout of handbags but to his credit referee Owens restored order without any further action.
Cardiff Blues continued to dominate territory and possession, with Tom James, Alex Cuthbert and Josh Navidi all carrying hard but still the Dragons clung on.
Nick Williams carried from the back of an attacking scrum, holding the ball in one hand as if it was a child’s size three, and following sustained pressure James eased on the outside for a vital try that had been coming.
Evans was unable to add the extras to draw level but the Blues were instantly back on the attack as Josh Navidi intercepted from deep inside his own half.
The versatile back-row forward displayed remarkable pace to rampage forward but Tyler Morgan and Hallam Amos were able to use the angle and they were able to hold Navidi up over the line.
However with young props Assiratti and Corey Domachowski in the front row they turned the screw at the scrum and at the second time of asking Cuthbert crashed through the defence to give his side the lead.
Evans slotted the simple conversion to make it 29-24 with 15 minutes remaining and the young fly-half dummied, and quickly raced through the Dragons defence to compound the visitors’ woes.
The Newport-based outfit vaguely threatened as Sarel Pretorius went on the counter but when his side were penalised Tomos Williams showed no mercy.
He displayed his electric pace as took a quick-tap and then sent Morgan free to scorch under the sticks for his second.
There was a late consolation try for the visitors, who secured a bonus point when Lloyd Fairbrother crossed the whitewash in the final moments.