Llanelli, unbeaten since September, extended their run with a 37-17 victory over Pontypridd. Lee Williams, Phil John, Craig Richards and Shaun Hopkins scored for the Scarlets, with Dan Evans adding the extras.
Leaders Newport were also winners: Scott Williams and Dan Pattison tries led to a 23-11 win over bottom club Glamorgan Wanderers.
The weekend's biggest shock came at Bedwas, where reigning champions Neath were beaten 20-18. The All Blacks led 18-3 in the 51st minute, but a late Jamie Lewis score and an even later penalty try gave the men from Bridge Field a surprise win.
Third place Aberavon took advantage of a double Swansea sin binning to run out 33-12 winners at the Talbot Athletic Ground. Swansea, who scored their first try for three games when Ben Lewis crossed, were trailing by just one point early in the second half. However, yellow cards for David Blyth and Ian Evans allowed Richard Carter, Simon Peters and Robbie Morgan to add to Jamie Davies's first half score.
Ebbw Vale recorded a narrow win over Cardiff. Ebbw Vale were 19-9 down after 70 minutes but Kristin Owen try gave the Steelmen hope, before prop Ian George crossed for a 79th minute winner.
It also went right down to the wire at Llandovery, where a late penalty try gave Bridgend a victory. A Viv Jenkins brace and an Emyr Phillips score had given the Drovers a scent of victory, but a try by Darren Simpson and the boot of Gareth David kept the Ravens in touch, before Llandovery collapsed a maul on their own line, with David slotting over the vital conversion.
At Pandy Park the fixture between Cross Keys and Maesteg was called off 15 minutes before kick off due to a waterlogged pitch.