The hosts had led 15-6 at half time and eventually prevailed 30-26 as Llanelli came roaring back. It was not enough to secure the win though and with Bedwas, Llanelli and Llandovery now separated by just seven points, competition for the two places in the play-off semi-final looks intense.
A first half double from Elliot Jones had given Neath a great start, the wing crossing for his first score inside two minutes. And with Leon Ward adding a third try on the verge of the half time whistle, Neath boasted a comfortable nine point lead.
Two penalties from Jordan Williams were all Llanelli could manage in reply.
But in the second half, Williams added a try to an earlier score from Nic Reynolds and booted two conversions and two penalties as his side roared back.
It was not enough though and Steffan Jones' score, which preceded the Llanelli onslaught and a later penalty try edged Neath home.
A full five point haul was perhaps unexpected for a Neath side who had made a number of changes from their SWALEC Cup semi-final win last weekend.
They started brightly though and were ahead in just the second minute as Jones dabbed down for his first of the day.
Williams, pulled a penalty back for Llanelli but the fired up Blacks extended their lead after half an hour, Jones, jinking past three players to complete a double.
The conversion from Rory Morgan-Williams, on permit from Bryncoch, was wide before Williams added a second Llanelli penalty. That was not the end of the scoring though and following a rolling maul which started full 30 metres from the Llanelli line, Ward added a third score for a 15-6 interval advantage.
It turned out to be a vital try as Llanelli, no doubt given a rollicking by Anthony Buchanan, pushed them close in the second half.
Initially though, it was more of the same as Steffan Jones barrelled his way over after 42 minutes for Neath's bonus point try and a 20-6 lead.
Llanelli refused to lie down though and in a 15 minute purple patch, they suddenly found themselves back in front.
Williams added a third penalty, converted a nicely worked try from Nic Reynolds on 55, and showed his undeniable quality with a jinking run to the line to get his side back into things.
And after Williams converted his own try, a shell-shocked Neath now trailed by three. That deficit got bigger with another Williams penalty before Bowdy Davies responded for Neath with nine minutes left.
The score made it 23-26 but with two Llanelli men in the bin following yellow cards, Neath sensed an opportunity.
A succession of Neath scrums turned the screw and with Llanelli light on numbers, there was no other option than for a penalty try to be awarded.
Davies converted the score to dent Llanelli's play-off hopes.