Hard-earned wins at venues such as PSNI and Portstewart may not make any Irish Cup highlights reel but count as crucial steps closer to an end-of-season Windsor Park showpiece.
If Portadown’s knockout campaign culminates in Irish Cup glory then results such as Saturday will take on added value.
Difficult conditions in the air and on land limited the opportunity for passing football but Portadown produced before the final whistle thanks to Gary Twigg and Darren Murray.
Third-tier Portstewart worked hard to restrict the visitors’ attacking threat.
Tim Mouncey attacked a free-kick delivery from 18-year-old Jake Richardson without success then Peter McMahon had a shot blocked following good work by Ross Redman before half-time.
Mistakes by Redman and Garry Breen offered the hosts hope of a cup shock but, overall, Portstewart failed to trouble David Miskelly.
Any sense of tension came from the referee’s stopwatch as time ticked by without an opening goal.
Darren Murray offered a second-half threat following, respectively, work by Robert Garrett, Shea Conaty and Mouncey - with one low drive the wrong side of the post and another over the bar before Joel Maddison’s fine stop pushed away his close-range snapshot.
Twigg made his mark on 76 minutes by scoring the tie’s first goal at the second time of asking following Sean Mackle’s cross.
Murray then gained a reward for his efforts by reacting to convert a rebound off Mouncey’s long-range drive.
PORTADOWN: David Miskelly, Ross Redman, Keith O’Hara, Garry Breen, Peter McMahon, Darren Murray, Tim Mouncey, Gary Twigg, Shea Conaty, Robert Garrett, Jake Richardson. Subs: Billy Brennan, Sean Mackle (on for Conaty, 65 mins), Paul McElroy, Jordan Lyttle, Marcio Soares (on for Twigg, 84 mins).