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.
Beating Merthyr has boosted Carmarthen Quins hopes of reaching a top eight spot in the Principality Premiership. Quins captain Haydn Pugh is delighted with his team's progress and is determined that everyone from the Under 6s through to the senior team, enjoys the ride.
When the Wales squad were asked to nominate individuals who played a big part in their early playing days, Wales and Dragons full back and wing Hallam Amos thought of his former Monmouth School rugby coach John Bevan.
Sam Cross and Luke Treharne have been named as co-captains of the Wales Sevens side as head coach Gareth Williams names his 12-man squad to play in the first leg of the HSBC World Series in Dubai next weekend.
Bedwas head coach Steve Law and players Nicky Griffiths and Alun Rees extol the virtues of the close knit club as they prepare to host third place RGC 1404 - who are one place head of them on the Principality Premiership points table - on Saturday.
Many of the Wales squad have said Diolch (thank you) to someone who played an important part in their early playing days by nominating them to be invited to the Wales v South Africa match. One person, Gowerton Comprehensive geography teacher Mr Dean Mason was nominated by two of his former pupils, Dan Biggar and Sam Davies.
The second WRU disability rugby pilot has been delivered, this time in Caerphilly schools, culminating in a festival at the Caerphilly Centre of Sporting Excellence, Ystrad Mynach tomorrow. Plans are in place to set up a Disability Rugby Club in Newbridge to provide long-term playing opportunities.
WRU TV: Hear from inside the Wales camp as Neil Jenkins discusses this weekend's clash with South Africa and how the squad are looking to put in a strong performance to round of the 2016 Under Armour Series