Flanker Ellis Lloyd wrapped up a bonus-point victory for the Amman valley club after wing Wayne Price, centre Mike Errand and No8 Chris Jones had all crossed in a 28-11 victory.
Aaron Halfe’s reply for Pencoed never looked to be enough to save the Bridgend side from a third straight loss of the Division Two campaign.
They are not alone in making a slow start to the season with three other clubs also searching a first win three weeks in. Mumbles were edged out 35-31 at Pontyberem, Aberavon Quins picked up a losing bonus point at BP Llandarcy 16-10 while Aberystwyth were out-gunned 43-7 at Loughor.
Maesteg marched to the top of the table after running in five tries in their 35-18 win at Kidwelly.
In Division Three there were few problems for Laugharne, who dispatched Gorseinon 49-19, or Llandeilo who made similarly easy work of Llanybydder 41-3.
Andy Andy Llewellyn scored twice as Seven Sisters won 48-16 against last year’s Division Three south-west surprise team Bryncoch, still coming to terms without coach and former Wales centre Leigh Davies.
Amman United stormed past Tumble 49-14 in Division Four while Taibach won a third game in succession, 34-12 against Resolven