Heavy fog at Shamrock Park could not hide the gap in quality as Linfield’s title push gained another boost but Portadown suffered a significant setback in the battle to beat the drop.
Linfield held a 2-0 lead at the interval then fired home three goals in seven second-half minutes, plus Ryan Strain had his penalty kick saved with the final shot.
Stephen Lowry fired home the first to cap a well-worked exchange with Kirk Millar. Paul Smyth drilled in a low shot from distance to double the gap by the break.
Millar then got on the scoresheet with a long-range strike and Jamie Mulgrew rounded off a slick Linfield counter-attack with a delicate touch to control a cross and measured finish.
Mark Stafford forced home the ball from a few yards after hesitancy in the penalty area by Portadown to clear Mark Haughey’s downward header.
“The first goal in any football match is key and, thankfully, we got that plus have good players who can hurt teams and score goals,” said Linfield manager David Healy. “We started with the right tempo and never really looked back after that first goal.
“The disappointing thing when you look at it is we scored five times and probably could have scored a few more.
“If winning or losing, at half-time you always ask can we be better in the second half.
“The players were told, you look at the league table and Portadown are not a minus-one team as they have some good players and we knew we needed the right attitude.
“They’ve not been out of too many games this season, probably apart from the two games they’ve played us and then Dungannon Swifts, so I knew it would be tough enough.
“We’ve struggled down here before so it’s pleasing to come away with the three points.
“The fog was fine at the start of the second half then it became harder to see as the match went on but not a problem.”
It was an afternoon to forget for the Ports, with Carrick Rangers’ win increasing the gap at the bottom of the Danske Bank Premiership.
Directors have been in talks this week with candidates for the manager’s job on a full-time basis as interim boss Vinny Arkins does not hold the required UEFA ‘A’ Licence qualification.
Names linked with the permanent position include Paul Doolin, Roddy Collins, Niall Currie, David Johnstone, Colin Malone and Trevor Williamson.
Arkins’ post-match focus centred on the previous 90 minutes rather than the future.
“Linfield are a good side capable of putting any team under pressure,” said Arkins. “But it is frustrating from our viewpoint that we look back and four of the goals were certainly preventable.
“We gave away possession too often and kept trying to play one-touch football so must learn from our mistakes.
“One bonus was trying to get something positive from the game by giving young Zac Wilson some more playing time.”
PORTADOWN: McGaughey, Carson, Breen, O’Hara, Byrne, Simpson (Hughes, 56), Garrett, Shannon, Mackle (Wilson, 64), Kirwan, Haire (Parker, 76).
Subs not used: Larkin, Mouncey.
LINFIELD: Carroll, Stafford, Haughey, Callacher, Waterworth (Strain, 75), Lowry (Fallon, 64), Millar, Ward, Mulgrew, Quinn, Smyth (Gaynor, 55).
Subs: Casement, Clarke.
Referee: Mervyn Smyth.