Bridgend Athletic twice had the chance to equalise late on but outside-half Stuart Morris was unlucky enough to hit the post on both occasions.
This defeat meant Builth Wells had the opportunity to jump into top spot, and they did in some style through a 38-15 victory over Gorseinon.
Dorian Davies was the hat-trick hero for the Bulls, crossing the try line for three of their six tries.
Loughor leap into second spot over Bridgend Athletic by virtue of tries scored, thanks to a 22-7 bonus point win against BP Llandarcy.
This means there are now three teams locked on 59 points at the summit of Two West, with Builth Wells top on the basis of having an extra win.
In Division Three West, leaders Aberystwyth were narrow 26-22 winners at Newcastle Emlyn, but could not secure a bonus point on their travels.
This allowed Pontyberem to take themselves to within one point of their rivals, after they hit four tries in a 27-17 win at Laugharne.
Aberavon Quins stretched their lead at the top of Division Three South West to 11 points, as they won 15-7 at Skewen while second place Glynneath lost 21-17 at Maesteg Quins.