gap Connah's Quay failed to gain the point that would have guaranteed their progression into the last eight, but will almost certainly qualify as one of the highest-placed runners-up if they are overhauled at the top of the group.
Porthmadog gained a much-needed win to restore flagging confidence, with striker Aden Shannon notching a brace against the clun he played for last season.
He wasted little time in opening his account, heading past makeshift keeper Ben Alston from a Ceri James cross and, within minutes, Tomi Morgan's side doubled their lead when a free-kick was converted by Mark Gornall with a superbly-struck shot.
Nomads did up their game, but were unable to trouble keeper Richard Morgan, and Port thought they had scored again, only for Mike Thompson's effort to be flagged offside.
Quay also had a goal disallowed before half-time when Sam McNutt strayed too far forward and Morgan pulled-off a good save from Danny Forde.
Port controlled most of the second spell and added their fourth on 75 minutes, Thompson squeezing a shot via Alston into the back of the net.
Report and stats courtesy of welsh-premier.com