Junction overturned a 1-0 half time deficit to turn the tables and inflict a first home league defeat of the season on Premier Division leaders St Asaph.
Ryan Potts broke the deadlock on 21 minutes with his 19th goal of the season in all competitions, but the picture changed from the midway point of the second period.
Jack Williams made it one-apiece on 66 minutes with his 14th goal of the campaign.
Curtis Cooper then edged the Railwaymen in front on 77 and there was still time for Junction’s newest signing to make his mark.
The experienced Patrick Hamid, who joins from Rhuddlan Town, made it 3-1 with a debut goal in the 88th minute soon after coming on as a substitute.
And to complete a day to forget for Saints, they had Simon Fawcett red-carded in the 90th minute.
Sam Jones marked his return to Llannefydd is amazing style with a four-goal salvo against Glan Conwy.
Jones, who recently rejoined the village side from Llanrwst, was in deadly form for Gwyndaf Pritchard’s men, who are now just a point behind leaders St Asaph with a game in hand.
To make it a pretty special day for the Jones family, Sam’s brother Ed provided four assists.
Simon Roberts, Nico Clwyd and Ciran Jones were also on the mark for Llan.
Will Arnold grabbed Glan’s consolation.
Kai Davies was a hat-trick hero for Mochdre Sports as they rattled up eight against Bro Cernyw at Swan Road.
Josh Grimshaw added a double, while there were also goals for Fin Jones, Niall Owen and Scott Brown.
Ryan Lawson, Gethin Vaughan and John Gardner replied for the visitors.
Daniel Williams (3), Billy Sieben (2). Ricky Jones, Ian Pattinson and Jamie Jones combined to ensure Phoenix hit eight on the road.
Gethin Roberts responded from the penalty spot for Blaenau.
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