Whitland surged into a 27-13 lead by half-time, with tries from front-row forwards Gareth Lloyd and Dafydd Phillips. But their lead was cut back and a last minute penalty from outside-half Stuart Morris secured the win.
TATA Steel kept up the pressure on Narbeth with another high-scoring win away at UWIC. Steel benefitted from two tries from interceptions and did not look back despite being down by six points at half-time.
Full-back Simon Evans crossed twice for TATA, who were also awarded a penalty try. Outside half Diggy Bird converted all four tries in the bonus point victory.
Carmarthen travelled to lowly Bonymaen and had no trouble in securing their first win at Parc Mawr for more than 10 years. Full back Mike Sauro was the star of the show with a try, a conversion and three penalties. Flanker Luke Owens added a third try in a comfortable win.
The tries continued to flow as Bridgend Athletic beat Waunarlwydd 44-27. Jonathan Phillips and Rhys-Ward Jones each scored twice as the home side crossed the white wash six times in total.
Stephen Lewis added four conversions and two penalties as the home side claimed a bonus point win. Despite defeat, Waunarlwydd scored four tries themselves in what was an action packed second-half. Tom Gronow and Lee Evans were among their scorers but they were well beaten in the end.
Two tries from captain Dai Atkins secured an easy win for Llanharan over Tondu. Nathan Huish and Bill Carey also crossed with Chris Williams adding 13 points with the boot.
Tondu were not helped by a yellow card for Tom Piper and they had only three Paul Smithson penalties to show for their efforts.
Elsewhere, winger Mike Davies scored twice in Llanennech's 25-16 win over Ammanford. Lee Davies and captain Ellis Phillips also went over as his side moved up into fifth place.