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.
WRU TV were on hand at the launch of a major new commercial deal with WRU and Mercedes-Benz South Wales (part of the Sinclair Group), which sees the family company become an official supplier to the Welsh Rugby Union
On the back of the recent Women's Rugby World Cup, the WRU has launched a revitalised Women's and Girls domestic seasonal structure, and the future is looking bright.
Go to www.wru.co.uk/tryourgame for more information
Roger Lewis talks to WRU TV at the announcement of a new £60 million Rugby Services Agreement (RSA) which provides a new and positive contractual relationship between the WRU and its four Regions for the next six years has been agreed.
The Welsh Rugby Union has announced a major new sponsorship deal with Gullivers Sports Travel which will make the UK's leading, and longest established, multi-sport tour operator, an Official Supplier for the rest of the decade.
Having taken part in seven World Cups as a player and coach, Liza Burgess hopes to go out in style this afternoon when Wales take on Australia in the Play-off for seventh and eighth place in the Women's Rugby World Cup in Paris.
WRU Head of Rugby Josh Lewsey met with volunteers across the game earlier this week, championing their role in the sport. He was joined by Wales captain Sam Warburton for part of the day as volunteers took part in a 'Try Out' event for the 2015 Rugby World Cup
Wales Women may not have got the results they wanted recently on the field, but off it they have made massive strides in strength and conditioning - and that is in no small part due to S&C coach Sam Dodge.