The Od Parish ran in eight tries to bewilder Blackwood by 48-7 and move 15 points ahead of second-placed Llanharan who now have five games in hand after their game against Tredegar at Ebbw Vale was called off.
A conversion by Mark David, returning after injury, took them over 1,000 points in 24 matches with Grant Epton's two tries taking him up to 22 and to leading try-scorer in the division.
Carmarthen Athletic defeated Glamorgan Wanderers by 37-15 win in which Julian Howells kicked 17 points, including conversions of all four tries.
Llangennech gained a 39-7 win over Treorchy with flanker Gareth Bateman grabbing two of the six tries and Bonymaen centre, police officer James Davies, ran in three of his side's six tries in a 46-14 win over Rumney with five conversions and two penalties by fly half Gareth Jones.
Narberth led Beddau 19-3 at the interval and held on for a 19-15 win as hooker Craig Hawkins played a stormer as a flanker with two tries and Whitland came back from 5-14 down to topple UWIC by 20-14.