Nantymoel went into the match in fourth place on the table, only one point off the top after winning their first three matches of the season. They came out of it bruised, battered and sick of the sight of the Bargoed midfield pairing of brothers Rhys and Darren Humphries, who scored five tries between them.
Pill Harriers went from first to third in the table as they lost their unbeaten record at Llantwit Fardre, who go top after the 23-17 victory. Both sides scored three tries, with Llantwit winger Gareth Morgan adding a vital eight points with the boot.
At the other end of the table, Brynmawr are still looking their first win after a 41-10 hiding at home to Abercynon, and Tredegar fell 27-18 to Llantrisant, for whom winger David Owen scored a brace of tries and fly-half Ian Worgan kicked 12 points.
New Tredegar were the unluckiest club in Wales on Saturday after their Division 3 East match at second-placed Rhymney was abandoned in the second half, with the visitors leading 18-17.
The match had been held up for 40 minutes with by a neck injury to Rhymney lock Adam Brain, and was called off when Bedlinog referee Phil Davies pulled up with a hamstring injury.
With the Rhymney match being abandoned, the Pontllanfraith-Old Illtydians game being postponed and Nelson producing and emphatic 40-12 win over fourth-placed Senghenydd, division leaders Pontypool United went clear at the top with a 15-0 victory over Fairwater. Paul Dale-Nash and Scott Bendon scored for the home side as mid-table Fairwater failed to get on the board.
In Division 3 South-East, Pencoed remain on top after a 35-12 win over Tylorstown, while Taffs Well made it six from six with a 41-10 win over Dowlais to remain top of Division 4 South-East.
It's a log-jam at the top of Division 4 East, with Newport HSOB and Trinant both losing their unbeaten records. Newport's 27-20 defeat at home to Tredegar Ironsides and Trinant's 20-14 loss at Garndiffaith means there are five clubs locked at the top on 12 points.
At the other end, Monmouth secured their first victory of the season - a 22-5 result at winless Oakdale inspired by a 60-metre try from scrum-half Gareth Morgan.
In Division 5 East, Machen and Bettws are still unbeaten after Machen trounced RTB Ebbw Vale 62-14 and Bettws beat Blaenavon 26-15.
Caldicot and Ynysddu both went into their match looking for their first win of the season - and they're both still looking after a 10-all draw.