On a night of low expectations, Portadown produced a win against the odds and against the history books to walk away from Windsor Park with three league points for the first time since December 2002.
Friday’s city trip suggested another frustrating fixture as, too often in the past, Portadown sides have appeared to wilt under the Windsor Park pressure.
The absence of a recognised striker from the starting line-up due to suspension and injury added to the sense of concern within the Ports fanbase.
The majority hit the road in hope rather than expectation and many felt before kick-off that, irrespective of the final score, an evening without additional suspension or injury problems would prove positive in preparation for the Irish Cup tie.
It was a different story at the final whistle as players and fans united in celebration at a memorable victory.
Warren Feeney’s goal, a glancing finish off Michael Carvill’s cross, handed Linfield the upper hand early on but Portadown’s confidence increased as play progressed.
Peter McMahon worked hard as a solo outlet at the head of the attack - with support from Mackle, Michael Gault and the ever-improving Shea Conaty.
McMahon, Mackle and Conaty - in particular - can gain confidence from such key performances within the team framework. One combination between Mackle and McMahon provided a clear scoring opportunity before the break but the latter’s shot on the run curled wide of the target after battling play by the former to retain possession.
Andy Waterworth hit the crossbar in the first half and Linfield increased the pressure across the early stages of the second but required a penalty kick to force a significant sight of goal.
However, David Miskelly moved to his right and displayed strong hands to push away the drilled effort down the middle by former team-mate Aaron Burns.
This sparked a superb period for the Ports, with Chris Casement marking his return from injury with a free-kick delivery that Jimmy Callacher could only steer past his own goalkeeper.
The main moment to savour arrived on 88 minutes when clever work along the left ended with Conaty - who also hit the crossbar - threading a measured pass behind the Linfield backline for the tireless Mackle to collect and slot home.
More successful Portadown sides have left Belfast with less and the true lasting value of Friday will become clear if this current group can push on from that win and add to the trophy cabinet.
Victory this weekend would provide the perfect second step down that road...
PORTADOWN: David Miskelly, Chris Casement, Ross Redman, Keith O’Hara, Chris Ramsey, Peter McMahon, Sean Mackle, Tim Mouncey, Michael Gault, Shea Conaty, Robert Garrett. Subs: Billy Brennan, Marcio Soares, Ken Oman (on for O’Hara, 83 mins), Paul McElroy, Jake Richardson.