Llandaff North wing Will Breckonridge scored a club record eight tries as his club thrashed Ogmore Vale 115-15 in their South-East division match at Hailey Park.
Vale had no answer to the North, who are bidding for runners-up spot after Llandaff had already clinched the title three weeks ago. They scored 19 tries and former Cardiff Youth fly half Matthew Maunder goaled ten of them.
Llantwit Major are a point ahead of the North, but have one match less to play. They won, however, by 60-7 at Rhiwbina and now meet the North on Saturday.
Trinant had already won the East title, but their final match brought their best win of the season as they dismissed hot rivals Oakdale by 12-3 with Jason Jones (3) and David Morgan kicking penalties against one by Greg Jones.
In the North, Denbigh took over at the top after defeating Bangor 59-21 and Welshpool held off Bro Ffestiniog by 26-12 to keep in third spot.
Resolven took advantage of an Aberavon Green Stars tour to Ireland by winning 43-12 at Pontardawe and taking over the leadership of the South-West.
In the West, Cefneithin's 15-3 win over Pembroke pulled them level on 48 points with Crymych with both clubs having four matches to play. Pembroke's loss leaves them with no hope of a top two spot and fourth club Pontyates also fell to defeat.