Cardiff Rugby continued their remarkable run against the Dragons as they recorded a 19th straight league win over their near neighbours.
It’s a bonus point victory which takes Matt Sherratt’s team up to the giddy heights of fourth in the URC table.
After a closely contested first half, they took charge with three tries inside ten minutes either side of the interval.
Flanker Alex Mann and wing Harri Millard crossed before the break to secure a 17-9 lead, with fly-half Callum Sheedy and centre Rey Lee Lo then going over to wrap up the bonus point inside 50 minutes,
Sheedy finished with a 16-point haul after landing five shots at goal, while classy Wales full-back Cam Winnett was named Player of the Match.
The visitors did battle back with two tries in the final quarter, but Cardiff saw the game out to take maximum points.
You now have to go back to December 2014 for the Dragons’ last league win over their east Wales rivals, with the teams set to meet again in a few weeks time in a Boxing Day clash at Rodney Parade.
It was a welcome result for the hosts in front of a 9,638 Arms Park crowd, but it did come at a cost, with prop Ed Byrne and flanker Ben Donnell both picking up injuries.
That followed on from No 8 Mackenzie Martin being forced off with a shoulder problem earlier in the day, while playing for Cardiff RFC in their 27-10 Super Rygbi Cymru victory over Pontypool.
That fixture was the first part of a double header at the ground amid something of a festival of rugby.
The second game of the day saw a return to URC action after a four week break for the autumn internationals.
When the play began, it was Cardiff who opened the scoring through the boot of Sheedy, but they were then forced into a change after just 11 minutes when Ireland loosehead Byrne limped off to be replaced by Corey Domachowski.
Three successful penalties, amid a couple of misses, from skipper Angus O’Brien gave the Dragons a 9-3 lead, while there was another injury blow for the hosts when Donnell collided with team-mate Millard and had to leave the field using his jersey as a sling to support his arm.
Donnell was replaced on the blindside by Mann and the Welsh international was to make an instant impact on just his second outing of the season.
First he charged down Rhodri Williams to create a threatening position and then, on the half hour, he touched down for the opening try of the game.
After Josh McInally leapt high at a close range lineout, Alun Lawrence carried strongly down the narrow side and then Daf Hughes popped a short pass to Mann who drove over, with Sheedy adding the conversion.
But the hosts were on a final warning for penalty offences at the point and soon had lock McInally yellow carded for preventing release at a ruck.
However, they made light of being down to 14 men as they took a grip on proceedings.
A superb weaving run from wing Millard was followed by a kick through from Sheedy for the returning Josh Adams who managed to get his boot to the ball.
The touchjudge ruled he had been out of play when doing so and raised his flag, but that decision was overruled giving Cardiff an attacking scrum.
From there, they piled on the pressure and, with the Dragons now on a warning for offences, the numbers were levelled up when hooker Brodie Coghlan was sin binned for getting in the way of an Aled Davies pass while in an offside position.
Then, three minutes into stoppage time, the sustained onslaught was rewarded with a converted try.
With advantage being played following a big scrum shove, Ben Thomas threw out a long floated pass which Millard took low down before coming back against the grain to cut inside three defenders and reach the line.
Turning round with a 17-9 lead, Cardiff went further ahead three minutes into the second period with a score set up by Adams on his first outing after six months out with knee and hernia issues.
Via a quick tap from Davies off a scrum free-kick, Adams sliced through in midfield, making some 40 metres before being hauled down.
The ball was then recycled with Winnett dummying through and sending Sheedy over, with the No 10 converting his own score.
Cardiff now had the wind in their sails and secured the bonus point fourth try on 50 minutes.
From a tap penalty under the posts, back row pals Lawrence and Thomas Young combined nicely, with Young giving the scoring pass for Lee Lo to cross for another converted score.
To their credit, the Dragons didn’t let their heads drop.
Just past the hour mark, replacement scrum-half Morgan Lloyd dummied his way through from a ruck and broke a tackle to reach the line.
Then, eight minutes from time, there was another converted try courtesy of a sub, with prop Aki Seiuli forcing his way over from close range after heavy pressure.