Scrum -half Meiron Thomas crossed twice for tries while back-row duo Scott Davies and Chris Edmonds also touched down for Mountain Ash to secure a well earned victory. There was more good news for the men from Duffryn Pennar Parc when Rhydyfelin sprung a surprise on the league leaders, with a 25-21 victory. Mark Palmer, Lee Scarfe and David Gratton all scored tries for Rhydyfelin, while Gareth Walters scored the solitary try for the hosts.
Elsewhere there was basement battle between eleventh placed Newport Saracens and twelfth-placed Garndiffaith. The Saracens came out on top and ran in seven tries in a 47-12 victory. Blindside flanker, Carl Townsend, was a constant threat and stormed over for a hat-trick of tries. Townsend was joined on the scoreboard by Dale Leith, who grabbed his own brace, Tom Piper and Lewis Culverwell.
In Division Three East Abergavenny continued their march towards promotion with a 36-8 win over Tredegar Ironsides, William Harris, Stephen Evans and Gareth Carney among the scorers at Bailey Park.
Fleur De Lys also maintained their impressive run of form and keep the pressure on the league leaders thanks to 41-20, six try romp over Nelson. Scrum half Daniel Cook, no.8 Lee Taylor, wing Jamie Henthorn and centre due Ieuan Morris and Brett Green and crossed for tries.
There was a top-of-the-table battle in Division Four East where second-placed Talywain travelled to top side Abertillery BG. Talywain came out on top and sealed a hard-fought 15-13 victory. The visitors raced into a 12-3 half-time and held on for victory despite a second-half Aled Penn try for the hosts.