The tie then swung Glynneath’s way in the second half with first James Varden going over and O’Reilly converting to edge them in front for the first time, 18-17.
And then Alex Burton’s unconverted try sealed the deal and sent Glynneath – runners-up to Ammanford in the 2011 Plate final – into round three, where they will meet either Risca or 2018 winners Brynmawr.
Those two play their rearranged tie next Saturday, as will Treorchy and Bro Ffestiniog.
The postponed second round tie between Bedlinog, Plate winners of three years ago, and Abercwmboi has been rearranged for November 4.
Meanwhile the draw for the third round of the Plate has thrown up a repeat of last season’s final as Bonymaen look for revenge over holders Brecon.
