Ebbw Vale extended their lead at the top of the Swalec Championship and secured local bragging rights thanks to a narrow 13-19 victory over Pontypool.
Tries from Carl Meyer and Wes Cunliffe gave the Steelmen a 3-13 lead at halftime, and despite a Steve Pooler score a Ronny Keynes try secured the points.
At the other end of the table Beddau squeezed past Bridgend Athletic 17-15. Glen Slater scored twice as Beddau cruised to a 14-point lead but Bridgend rallied, with Steve Lewis missing a last minute conversion to secure the draw.
There was another tight game at Blackwood, with Alex Jenkins' last minute try giving Narberth a 30-28 victory.
Bargoed also won at the death as they beat Cardiff Met 16-17, with the whistle going straight after fly-half Joel Prosser converted Lee Peterson's try.
There was a more straightforward affair at the Welfare Ground as Newbridge sailed to a comfortable 31-0 win over bottom of the table Bonymaen, with Richard Powell converting all four tries.
Twenty points from Cody Rees gave Llanharan a 34-27 win over Tata Steel, a win which moves them clear of The Saints.
Tata Steel outscored Llanaran four tries to three, with Ross Pritchard going over twice, but the boot of Rees guided Llanharan to victory.
Elsewhere, RCG 1404 beat Tondu easily away from home. RCG scored eight tries, with braces for Hopkins and Hugh Grundy, as the Waterwheelers were easily dispatched.
Wales reached their first semi-final since 2013 in the opening round of this season's HSBC World Rugby Sevens Series in Dubai. WRU TV's Graeme Gillespie recaps on what proved to be an eventful tournament
Wales and Ospreys back row James King, who came through the North Wales age grade system, nominated North Wales Regional Community Rugby Manager Marc Roberts, in the WRU's 'Diolch' initiative where squad players thanked those who played a part in their rise to the top.
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