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.
GB7s women left their England base to train in Wales this week. Olympic Games hopeful Rachael Burford gives WRU TV's Graeme Gillespie her thoughts on Welsh teammate Jasmine Joyce - a 'one touch wonder'
The GB7s women's squad is currently training at Wales' Centre of Excellence where assistant coach Richie Pugh tells WRU TV's Graeme Gillespie some 'tough calls' will have to be made when it comes to finalising the 12 spots for Rio's Olympic Games.
Wales U20's Billy McBryde is looking forward to starting his first game against New Zealand this afternoon in the World Rugby U20 Championship where his side are looking to gain revenge from last week's pool defeat to the Kiwis.