There were also notable away wins for Penclawdd, Tonmawr and Kidwelly who saw Gwilym Ace prove a match winner with his try at Seven Sisters.
Aberystwyth began their season in Division Three with a bang, completing an emphatic 56-18 rout of Pontarddulais with eight tries. Richard Davies was on the mark as Tumble sealed a 16-0 win at Llangefni and Laugharne were pushed all the way home in their 11-10 win over Trimsaran.
Aberavon Quins wracked up a 45-5 win over Bryncoch in Division Three (south-west) while Cwmgors got the better of a close encounter at Skewen 7-3.
Cardigan ran riot in Division Four with a 53-0 thrashing of Milford Haven while Birchgrove set the standard in Division Four (south-west) with their 34-0 win over Trebanos.
St David's will want to forget their start to the new season after going down 31-0 at home to Fishguard & Goodwick in Division Five. Yet even that defeat was dwarfed by the day's biggest win, 70-0 for Ystradgynlais over hapless Swansea Uplands.