Fleur fly half Brett Green kicked five second-half goals after Rhymney had led 9-3 at half-time. Gareth Richards landed a penaty hat-trick and a drop shot for the home side, but Green's five penalties and a conversion of a try by centre Richard Jones did it.
Builth fy half Rob Lloyd scored two tries and five conversions as they beat Llantrisant 40-20, though the Black Army were only a point behind at the interval. George Jenkins (2), Lyndon Hammonds and wing Huw Lloyd scored the other Builth tries.
Llantwit Fardre routed hapless Dinas Powys 85-0 with Richard Langmead scoring 25 points while Risca gained a notable 26-15 win at Merthyr.
In the West, Tonmawr extended their bid for the title by winning 45-27 at Waunarlwydd and now lead Bridgend Athletic by six points with both clubs having two games to play leaving Tonmawr just needng one point to be champions.
It is still a dog-fight for runners-up after Bridgend's 44-38 amazing win at Felinfoel as Dunvant and Cwmllynfell closed to two points from them. Dunvant defeated Cardigan by 30-17 at Broadacre and Cwmllynfell did the double over Pencoed with a solid 30-13 win.