Bargoed and Caerphilly drew a thrilling game 35-35 with each side picking up a bonus point for scoring five tries a piece.
Caerphilly thought they were going to record the maximum of five league points until the last minute, when centre Darren Humphries' try was converted by Danny Jones to level the scores.
Blackwood remain in fourth after winning 31-22 at Llanharan, with No 8 David Brake scoring two of the four tries that earned them a bonus point.
Craig Griffiths scored the winning try for Ystrad Rhondda, who came back from 23-15 down to win 27-23 against Rumney.
UWIC jump to fifth after beating Newport Saracens 29-3 and Penalta saw off Beddau 20-15.
Camarthen Quins have now won eight from eight in Division One West, with Maesteg becoming their latest scalp in a 29-3 victory.
Tries from Ryan Llewellyn, Jamie Davies, Martin Morgan and Brian Edwards meant Quins recorded their fifth bonus point of the campaign.
Quins lead at the top of the table increased to 12 points as nearest rivals Tonmawr fell to defeat at Felinfoel.
Jason Howell scored two tries for the newly-promoted side with Rhodri Nathan kicking the rest of the hosts' points in a surprise victory.
Third place Whitland failed to capitalise on this result, as they were seen off 12-3 at Cwmllynfell.
Outside-half Neil Davies put over four penalties for Carmarthen Athletic, who leapfrogged Narberth in fourth on winning 17-8 at the Lewis Lloyd Ground.
Dunvant are still winless after going down 29-7 at home against Corus, whilst Llangennech won 18-10 at Bonymaen.