CSG had five of the Wales squad that had performed so well at the Five Nations Festival in Llandovery at the beginning of the month and their class shone clearly through.
Centre Luke Williams, scrum-half Aled Davies, lock Luke Hamilton and flanker Kirby Myhill all looked players of class as did prop Samson Lee who came on as a replacement.
Neath No 8 Dan Baker was Neath's one international and he, flanker Ollie Pardoe plus lock and skipper Luke Joseph battled hard but in vain against superior forces.
That CSG were only narrowly 10-7 up at the break was down to some desperate Neath defence and poor finishing by CSG in prime positions
Hamilton and wing Iolo Evans crossed before wing Nathan Brooks side-stepped through for a great solo try for NPTC converted by fly-half Cameron Clement but it was one way traffic after the break.
With skipper and lock Lawrence Reynolds leading by fine example in the loose, the CSG pack dominated in all areas and with the backs finding time and space to create a lot of openings, there were six more tries.
Scrum-half Aled Davies was at the heart of everything and tries from centre Williams, flanker Myhill (2), Evans, Hamilton and fly-half Nico Setaro were all reward for some well-supported running and dextrous handling.
Both sides threw on a raft of replacements and it was only justice that the non-stop and outstanding Pardoe charged through at the death for a well-deserved consolation try.
Scorers: CSG Tries: I Evans (2), L Hamilton (2), K Myhill (2), L Williams, N Setaro; Cons: N Setaro (2)
NPTC Tries: N Brooks, O Pardoe Con: C Clement
Earlier in the day Lewis Boys Pengam beat Ysgol Dyffryn Teifi from Llandyssul 24-21 to win the Welsh Schools Bowl.