Glantraeth took the lead after only three minutes with a bizarre goal as keeper Steve Thomasís long kick downfield found the net after being badly misjudged by the Llanrug keeper. On 11 minutes the home side made it two as Mark Thomas headed home at the far post following a deep cross from Rob Williams.
The Cymru Alliance champions were well on top at this stage and took a three goal lead on the half-hour mark as another long punt by Steve Thomas was headed on by Kevin Roberts and Richard Owen stole in to finish from close range.
Ten minutes into the second half Glan scored a fourth as good play by Anthony Hughes set up an easy chance for Kevin Roberts to finish.
Playing with the wind the Welsh Alliance side were putting up a much better show this half and pulled one back on 57 minutes as a powerful header by Owain Morris from a right wing cross gave Thomas no chance.
Richard Owen scored his second on 68 minutes after clever play from Rob Williams had created an easy scoring chance.
Llanrug were not finished though as with fifteen minutes remaining Morris fired a tremendous effort against a post.
Glantraeth: Steve Thomas, Emyr Rowlands, Darren Jones, Warren Gibbs, Gareth Owen, Nigel Barry, Rob Williams, Mark Thomas, Paul Rowlands, Richard Owen, Kevin Roberts. Subs used: Anthony Hughes, Neil Hughes