Llantrisant stormed four points clear at the top of SWALEC League Division Two after capitalising on Gilfach Goch's slip at Bedlinog.
While the early leaders were being kicked out of first place by Bedlinog's Richard Heath, who kicked four penalties to edge out Gilfach Goch 12-6 in a tight encounter, Llantrisant were making far easier work of Treherbert.
Second-row Sam Williams scored twice as Llantrisant ran in seven tries to take an early grip on the division ahead of their rivals.
Tredegar slipped to third after losing 31-24 to local rivals Brynmawr for whom flanker Gavin Napp scored twice while at the other end of the table, Fleur de Lys claimed their first win when Richard Jones' late try beat Rhydyfelin locked at 25-18.
Llanishen enjoyed themselves in the sun with a 52-6 win over Cardiff rivals Old Illtydians in Division Three south-east
while Treorchy gained another bonus-point win at Aberdare, 35-20.
Gwernyfed and Garndiffaith lead the way in Division Three after their victories, 29-7 at New Tredegar and 29-15 at Cwmbran respectively.
Barry Greenley, Paul Rees, Chris Voyce, Stuart Ornick and Nathan Rhys all scored as Llandaff lowered the colours of Division Four leaders Nantyglo, 29-21 in Cardiff to take over top spot themselves.
In Division Four south-west, Dowlais had little trouble dispatching Porth 48-12 while Jack Davies and Gavin Stokes both scored twice as Abercarn produced the performance of the day in Division Five East, beating Llanhilleth 37-7.
Barry scrapped out a second tight victory in a row, getting the better of Cilfynydd 12-7 in Division Five south-east.
The last five years have been an emotional rollercoaster on and off the pitch for RGC1404. Promotion to the Principality Premiership was the culmination of five years of hard work and investment in North Wales. WRU TV caught up with prop Joe Simpson, who was one of the first intake of WRU North Wales Academy players in 2010.
Ebbw Vale captain Damien Hudd picked up the biggest accolade of the night at the 11th Principality Premiership Awards Evening held at Principality Stadium, after leading his side to the title for the first time.
Wales assistant coach Robin McBryde is predicting a tough battle against England on Sunday despite the fact they may not be considered to be at full strength. Players will be out to impress Eddie Jones which makes England a dangerous proposition, he says.
Wales U20 captain Tom Phillips and performance psychologist Dr Rich Neil explain why spending three days at Monmouth RFC has further strengthened the togetherness of the squad ahead of the #WorldRugbyU20s