The victory will have given a huge boost to the Wales U19 side that faces Australia in the full U19 international at Pontypridd in 3 days time. Coach Justin Burnell paid tribute to "the great team ethic not of any side but of the whole squad of 26 or so players involved in the U19 set up" as he looked forward to Saturday's game.
There was mot much between the sides but Wales built up enough pressure, momentum and points to thwart a great rally by the tourists in the last 10 minutes.
A fine team try, scored by excellent full back Dan Evans, plus three penalties by fly half and fellow Scarlet Rhys Priestland had Wales 14-7 up, Australia's try coming from lock Sam Wykes, converted by fly half Ben Lucas.
When Australia threw on their heavy guns, it looked ominous for Wales but some wonderful team and individual defence withstood all the pressure.
Centres Luke Ford (Blues) and Gareth Maule (Dragons), locks Adam Brown (Dragons) and James Down (Blues) were heroic figures in a famous win.
Reebok Regional XV
Try: D Evans, Pens: R Priestland (3)
Try: S Wykes Con: B Lucas
Wales U19 Regional XV v Australia Schools
Dan Evans (Amman Valley CS/Scarlets)
James Norris (Newport HSOB/ Bettws HS/Dragons)
Gareth Maule (Newport /St Alban's RCS/Dragons)
Luke Ford (St David's Cath Coll/Blues)
Marcus Johnstone (Cross Keys/Dragons)
Rhys Priestland (Carmarthen Ath/Scarlets)
Darren Allinson (Pontyberem/Gwendraeth CS/Scarlets)
Nick Eaves (Treorchy/Blues) (rep Ryan Bevington (Porthcawl/Porthcawl CS/Ospreys 67')
Marc Breeze (Aberavon/Ospreys) (capt (rep Marc Jones (Salord Univ/Blues 50')
Keiron Jenkins (Treorchy/Blues) (rep Patrick Palmer (Ferndale/Y Pant CS/Blues h/t)
James Down (St Peters/Blues)
Adam Brown (Newport HSOB/Bassaleg CS/Dragons)
Sam Kiley (Bonymaen/Swansea Coll/ Ospreys)
Matthew Larsen (Gilfach Goch/Tonyrefail CS/Blues)
Lloyd Phillips (Narberth/Coleg Sir Gar/Scarlets) (rep Jon Jones (Bridgend Ath/Brynteg CS/ Ospreys 65')