Cardiff moved up the table with a thrilling 28-23 win over Aberavon at the Arms Park. Cardiff ran in four first-half tries to race to a 25-10 lead, but they could add only a penalty goal in the second 40 minutes as the Wizards stormed back into the match.
Promising fly half Dai Flanagan kicked three crucial goals as Pontypridd beat Swansea 14-10 at St Helen's.
Llandovery's 13-9 loss to Bedwas dumps the Drovers to the bottom of the table, with former cellar-dwellers Glamorgan Wanderers scoring a stunning 24-23 victory at Cross Keys.
Wanderers took an 18-8 lead into the break on the back of tries to Nicky Roberts and Gareth Morris, but Keys stormed back with a second-half brace of tries and it needed a Gareth McCarthy drop goal to keep the visitors' noses in front.
In the other game of the day, Llanelli ran in convincing winners over reigning champions Neath, 31-11.