Cardiff made it a quickfire double over their near neighbours as they rattled up five tries without reply in the first-half to continue their good end to the season.
Having beaten Caerphilly 38-8 at the Arms Park eight days earlier, they matched that tally in the opening 40 minutes to pile on the points and consolidate their fourth place in the Welsh Premiership.
It was Wales full back Rhys Williams who started the early flourish as he ran in a solo try after 18 minutes. By the interval Dean Dewdney, Adam Jones, Don van Vuuren and Ryan Powell had followed suit.
It was not the kind of start that former Cardiff and Wales great Mark
Ring had been hoping for from his home side, especially as they have a major European final to come in two weeks time when they face Castres in the Parker Pen Shield final in Reading.
Things went from bad to worse shortly after the break when Wales utility back Iestyn Harris hoisted his match tally to 20 points with a try and a sixth conversion to further stretch the lead.
But far from throw in the towel, Caerphilly rallied and two more penalties from outside half Luke Richards gave them new hope. Then two tries in the space of four minutes, both converted by Richards, breathed new life into the final quarter.
Wing Ryan Howells crossed for the first of the home tries and then lock Darren Davies romped over moments after his opposite number Heino Senekal was sent to the sin-bin. But all that was left in the game were two more penalties from the two outside halves and Cardiff hung on for victory.
Caerphilly: Tries: R Howells, D Davies; Cons: L Richards 2; Pens: L Richards 6.
Cardiff: Tries: R Williams, D Dewdney, A Jones, D
van Vuuren, R Powell, I Harris; Cons: I Harris 6; Pens: I Harris 2.
The Half a Game initiative is currently sweeping across Wales and proving a major success. The scheme aims to give every young player at least half a game every weekend. WRU TV recently visited a festival in Narberth where clubs have fully embraced the initiative.
Both Bargoed and Swansea were seeking their first win of the Principality Premiership season this afternoon. It proved a fruitful day for the hosts - not only did they win, but Bargoed claimed a try bonus point.
Cardiff managed to keep their unbeaten record at home intact, but only just as Bridgend made them work extremely hard before the Blue and Blacks secured a hard fought Principality Premiership win at the BT Sport Arms Park last night.
Former Wales back row Andy Powell gives a guided tour of The Wern, home of Merthyr RFC, who are determined to prove a lot of people wrong and make their mark in their first season in the Principality Premiership.
Wales Sevens head coach Gareth Williams looks back on the Rio Sevens success where he helped GB win silver. He believes the successful campaign is a huge boost to his Welsh squad as they prepare for another World Series, as WRU TV's Graeme Gillespie discovers
British and Irish Lions head coach Warren Gatland will be heading back home to take on the All Blacks next year where for him, success for 2017 is all about going to New Zealand and winning a Test Series.
Last week all roads led to Eugene Cross Park where defending champions Ebbw Vale hosted this season's launch of the Principality Premiership. WRU TV's Graeme Gillespie was there to capture the thoughts of Damien Hudd, captain of Ebbw Vale, and WRU Head of Performance, Geraint John.
Llandovery made it three in a row when they defeated Aberavon in the final of the National Foster's 7s at BT Sport Cardiff Arms Park on Sunday. On another eventful day of sevens, Newport claimed the Plate and the Dragons won the women's crown
Last week saw Cardiff welcome players from around the world for the 21st Golden Oldies Festival. The tournament features players over 35 years of age, and this year's event saw a select few represent the WRU in a 'friendly' against the Wooden Spoon.
Wales Under 18 captain Callum Bradbury is delighted to have seen his side claim a narrow 18-17 victory against a strong SA Schools 'A' side to end the three-match Under 19 International Series in South Africa on a high note.
The Wales U18 squad spent an emotional day in the drug-riddled townnship of Hout Bay. Hout Bay Warriors President Fred Johannes said the visit was 'the talk of the town' and will dream about the day everyday for the rest of his life.
RGC 1404's new head coach Mark Jones is hoping to build 'something special' in north Wales and is already looking forward to the development region participating in the Principality Premiership for the very first time.