CONNAH'S Quay looked as though they had forced the tie into extra-time, but a late brace from Carl Owen put Porthmadog into the semi-finals.
With Port trailing 2-1 on the night but level on aggregate, Owen was on hand to punish a fumble by Nomads' keeper Craig Bryan on 79 minutes.
Three minutes from time, the striker made certain when he latched on to a Mark Williams ball over the top to again beat Bryan.
Nomads had gone into an 11th-minute lead through Andy Griffiths, who sent his free-kick round the defensive wall for the ball to squirm under keeper Gerard McGuigan.
Williams equalised for the Traeth men with a header from Richie Owen's corner, but Nomads were back in front through Jamie Holmes on the hour.
Tommy Mutton almost got a decisive third goal, but Ryan Davies denied him with a last ditch tackle.
Report courtesy of welsh-premier.com