The Welsh All Blacks overcame a 30-minutes delay at the start of the second half as the generator ran out of diesel causing a floodlight failure and the home side themselves ran out of energy against an unrelenting wave of Neath forwards surges.
The Gnoll forwards created two pushover scores as they dominated the scrummage while locks Gavin Evans and Lee Bassett secured a plentiful supply of possession at the line-outs. The fact that the visitors failed to convert possession into points had more to do with some generous refereeing of the offside rule as the visitors found limited space in midfield.
Number eight Gareth Williams opened the scoring rounding off a flowing Ponty attack with an unconverted try, while Neath replied almost immediately as scrum half Gareth James collected his first try of the evening benefitting from a superb scrummage lead by the Neath front row trio of Paul James, Adam Matthews and Adam Jones.
Fly half Mike Thomas restored the home sides lead only for Dylan Pugh to level the scores midway through the first half. Any signs of a repeat half century of points performance as shown against Swansea in the previous round were not visible at Sardis Road even before the temporary gloom as Neath fell behind to a 15pts to 8 after Thomas scored a converted try at the posts.
After a hurried visit to the local garage and lights restored, Neath firstly levelled the scores after prop Paul James capitalised fully on the sinbinning of Thomas to crash over for a try.
While Ponty had their moments, the visitors took the lead for the first time in the match as scrum half James collected his second try at the base of another rapidly advancing Neath scrum. Pugh, growing in statue as the season progresses, added both conversions.
Left wing James Watkins seized on a Neath defensive error to score wide out and while the try went unconverted with Thomas missing all his second half attempts at goal, Pugh settled the visitors nerves with his second penalty of the evening to set up a final against the winners of friday evenings clash between Cardiff and Llanelli.
The WRU has launched a campaign to create a long term legacy for Welsh club rugby by highlighting the advantages of volunteering. Rhian Edwards, a volunteer at Seven Sisters, has enjoyed many benefits of her volunteering at a grassroots rugby club including being part of the Rugby World Cup volunteer workforce after being nominated by the WRU - and the WRU is asking for more people to develop their 'Welsh rugby roots'.
Wales head coach Warren Gatland and captain Sam Warburton say their first prioirty on Sunday in the opening game of the World Cup is to win against Uruguay and not get overly concerned with points difference.
With only days to go until the biggest rugby competition in the world begins, rugby fans visiting Cardiff this autumn will be able to enjoy a special display at National Museum Cardiff as part of the celebrations surrounding the Rugby World Cup.
Geraint John has taken up the new role of WRU elite coach development manager having arrived in Wales last week. WRU TV caught up with him at the WRU rugby department's strategy day at the Millennium Stadium.