The bonus-point success leaves RGC two points behind leaders Merthyr, with Carmarthen Quins in second position.
A brace of tries each from Tom Hughes and Andrew Williams and touchdowns from Iolo Evans and Rhys Williams were enough to secure victory
“It was a very good win for us because we have had some really tough games of late against Swansea,” said RGC1404 head coach Mark Jones.
“The last time we played them we won 35-34 so it was pleasing to get such a big win. I thought our pack were excellent giving us a really solid foundation to work off and we were very clinical when we created our chances.
“Fair play to Swansea they put us under some real pressure in the first half but we responded brilliantly in the second.
“With there being no end of season play-off’s anymore each game has a heightened importance and any points dropped will probably come back to haunt you.
“The table is very competitive at the moment but I think the next block of three games will go a long way to deciding who is challenging to win it and who is going to be down the bottom end of the table.”
Elsewhere, Carmarthen Quins winger Dale Ford scored four tries as his side thumped Bargoed 34-10 in West Wales to remain unbeaten at home this season.
Rory Pitman grabbed Cardiff’s 1,000th Premiership try with the first of brace from the No 8 powerhouse in a bonus-point, 31-19 home win over Neath.
The former Scarlets No 8’s tries helped the Blue & Blacks rise to sixth place in the table, while Neath are rooted to the bottom.
Eighth-placed Bedwas rose to the occasion scoring seven tries in their 41-14 home victory over Bridgend.
The home side’s win was their third victory in eight days following their 40-point thrashing of Neath and a comfortable Welsh Cup victory at Beddau.
Frozen pitches in Gwent accounted for the games at Rodney Parade, where Newport were due to entertain Pontypridd, at Pandy Park, where the WRU National Cup quarter-final dress-rehearsal between Cross Keys and Llandovery was also called-off and at Eugene Cross Park, where Ebbw Vale were due to host Merthyr.
