There wasn't a way back for Merthyr as in the second half. They were outclassed by a dominant RGC side. Richard Hopkins scored the third try for the North Wales side after with just ten minutes to go which concluded the match result.
Meanwhile, Heol y Cyw defeated high flying Treorchy 24-13 away in the other One East result. The result means Treorchy faced their third defeat of the season.
In Division Two East, Bedlinog leapfrog Rhiwbina to the top of the table after their convincing 43-18 victory over strugglers Fleur De Lys. Senghenydd's chances of being within a chance of being promoted got smaller on Saturday afternoon after narrowly losing to Abercynon 34-32.
The title race is getting fierce in Division Three East as all teams from the top three won their respected challenges. Newport HSOB retains top spot after their 21-10 win over Gwernyfed while second place Abertillery BG beat Abergavenny 28-18. Caerphilly remains in third after their comfortable 53-12 home victory over Tredegar Ironsides.
The biggest result of the day came from Division Six East as Blaina United turned on the style beating Cwmcarn 104-0. It is three games on the trot where Cwmcarn have conceded more than 50 points in a league game and hope to avoid the same fate away at mid-table side Forgeside on the 12th January.