RGC will face third place Bargoed on Saturday after they were left to wallow in a wet and windy washout at Bonymaen last weekend.
The Gogs suffered a surprise 7-5 loss against the league languishers but managed to maintain their fourth place spot on the SWALEC Championship table after coming away with a bonus point defeat in what was only their second away loss of the season.
Bonymaen, who were bolstered by a contingent of six permitted players from Welsh Premiership sides Llandovery, Camarthen Quins and Swansea, started ruthlessly early on.
Ian Brooks snatched the ball out wide to slide over in the corner for a converted try for Bonymaen.
Fly-half Dan Brooks wrested control of Bonymaen’s attack and kept the Gogs guessing throughout the first half.
RGC got a lifeline as Bonymaen were down to 14 men for a yellow card early in the second half, but soon after Gog front row Joe Simpson was also sent to the sin bin for an incident at the ruck.
An urgent try from Carwyn Ap Myrddin brought relief to the Northern fans after renewed RGC pressure, but Lewis Barker couldn’t convert the all important two points in the spiralling wind.
The Gogs spent the last 35 minutes camped in the Bonymaen half hungry for a second try but handling errors and slick conditions made for a tough day at the office and they failed to turn pressure into points.
RGC face third placed Bargoed at 2.30pm on Saturday, in what will be a crucial clash for table position before Christmas.