“We had two tries disallowed in the second half and had we got them I think the floodgates would have opened,” said Wales U18 coach Gethin Watts.
“Scotland made it difficult for us with their dogged defence and gained confidence from keeping us out,” he added.
Wales, building on their match against Leicester Academy looked cohesive when they moved the ball and in the early part of the match dominated the set scrums with three tighthead strikes.
Despite a crisp opening by Wales it was Scotland who claimed the early points with an opportunist try by winger Shaun MacDonald who got boot to ball after a spilled pass. Outside half Ben Cooper kicked the easy conversion but Wales’ power in the set scrums looked certain to bring a swift reply.
It did when Wales won a tighthead strike, the quick transfer of the ball to Ben Roberts giving the centre an unopposed run to the line for an unconverted try .
The Scots should have made more of a period of pressure on the Wales line but instead the visitors exploited turnover ball to create a long range try for winger Lewis Hudd, converted by outside half Jack Maynard for a 12-7 interval lead.
Scotland started well in the second half with two breaks by Cooper and then an interception from Irvine-Hess that all but produced scores. Wales, too, were twice close with fine efforts by winger Dafydd Howells and Roberts but it was Scotland who produced the first points of the second half with a try by Aberdeen Grammar wing Ed Farquharson from a rebound in the Welsh 22m area.
But in a thrilling finish Wales full back Hallam Amos showed his skill by skipping through two tackles to score under the posts, replacement Gareth Thomas adding the conversion points to seal a deserved win.
The Scots seemed certain to score after a siege on the Welsh line but turnover ball allowed Wales to counter attack, ending with winger Lewis Hudd sprinting in from 60 metres and stand-off Jack Maynard converting for a 12-7 interval lead.
Wales looked certain to increase their lead early in the second half only to have two tries disallowed. Scotland then came back into the game and levelled the scores with a try by winger Ed Farquharson . But a minute from full time Wales full back Hallam Amos skipped through two tackles to score the winning try, replacement stand-off Gareth Thomas adding the conversion goal to seal a deserved win.
Scorers
Scotland U18 Tries: MacDonald, Farquharson;Con: Cooper
Wales U18 Tries: Roberts, Hudd, Amos; Con: Thomson (2)
Scotland U18 : G Lowe; E Farquharson, C Mackenzie-Lawrie, F Robson, S MacDonald; B Cooper, A Glashan; J Malcolm, S Rendall, R Murray, A Cramond, N Irvine-Hess, C Simpson, J Jones, C Turner Subs used B Jardine, C Barnes, M McAndrew, N Herron, T Spinks, C Irvine, B Richardson
Wales U18 : H Amos; L Hudd, S Hughes, B Roberts, D Howells; J Maynard, L Crane; N Smith, E Dee, CLewis, J Helps, S Andrews, B Roach, S Matthews, J Benjamin Subs used J Sheeky, C Davies, S Clarke, G Thomson, C Woodall.
Referee: I Tempest (RFU)