Bargoed, who remain just a point behind the leaders, secured a bonus point in a comfortable 43-18 win against third-placed Newbridge. Full-back Andrew McLaughlin scored two of Bargoed's seven tries, with Newbridge prop Geoff Lewin receiving a straight red minutes before the half-time whistle.
Narberth's Sean Lloyd scored a dramatic winning try with minutes remaining, ensuring a narrow 15-14 victory at home to Llanharan.
Pontypool and Glamorgan Wanderers scored two tries each but it was the visitors who came out on top in a 17-13 win at Pontypool Park. The result leaves lowly Ponty a place off the bottom, while the Wanderers remain in 11th position.
Blackwood beat traveling Beddau 20-14 in the league's mid-table clash - Matt McGovern scoring one of the hosts' three tries.
Cardiff Met passed a stern test away to Tata Steel, winning 16-13. The home side scored two tries, but it was a late Matt O'Brien penalty that sealed the win for the visitors.
Whitland remain in 14th and last place after losing a kicking game at Bonymaen, 9-6.