It was Irish Cup folly as each side committed defensive blunders three times each at Shamrock Park — but Portadown took advantage twice through Gary Twigg to book a home tie with Championship side Ards.
“We weren’t at our best but Twigg was the difference and, having a home draw in the sixth round, we’re confident we’ll progress,” said Ports boss Ronnie McFall.
“We won’t be taking Ards lightly but a home draw is a big advantage and we’ll give it our best shot, especially with the cup being another route into Europe.
“In the meantime we’ll be pushing hard for a top six spot in the league. We’re only three points away, with plenty of football still to be played.”
All three mistakes by Dungannon created openings for ace marksman Twigg and he cracked home two, while substitute Josh Cahoon capitalised for the Swifts.
“Twigg was the difference,” said Swifts boss Darren Murphy.
“You can’t give him that sort of time and room and expect to make it through to the next round.
“We played the better football, had more possession and passed better. But we didn’t have Twigg’s finishing edge,” he added.
The Scotsman swooped after 12 minutes when he stole in, untracked, at the far post and side-footed home.
And he completed his double on 75 minutes when Fra Brennan made a total hash of a back pass, Twigg nipping in to score.
Dungannon answered three minutes later when the erstwhile immaculate Chris Ramsey got himself into a bit of a tangle after a PJ Lavery pass set up Cahoon to rifle home from about 12 yards.
The two Dungannon misses were either side of the break when Brian Gartland was robbed, but Brennan and Lavery missed the target, while Johnny Curran saved when Twigg was through one-on-one with the back four nowhere.
The game ended with Ports’ Darren Murray hitting the post.