Linfield still have a chance to make the semi-finals, but they have it all to do at Windsor Park in the second leg on December 17 if they are to keep alive their interest in the competition.

This was no fluke result, and Linfield's David Jeffrey was the first to accept this declaring: "Portadown were worthy winners – without a shadow of a doubt. In fact, their winning margin could have been even more decisive."

Portadown, playing in front of their biggest crowd of the season, were in fantastic form.

This was their eighth win in a row in all competitions, and it was also Portadown's first victory over Linfield in six years. No wonder the jubilant home crowd gave their players a standing ovation as they came off, and it was certainly a memorable night for the team which is playing in a lower grade due to a well publicised administrative error.

The performance proved beyond a shadow of a doubt that Portadown should be playing their football in the premier league, and this win will be a real tonic as they continue their bid for promotion.

It was a dismal night for an out of sorts Linfield, who failed to recapture the fight and the passion which carried them through against Crusaders at Seaview on Saturday.

Only once or twice did they threaten danger, and while it is true that they were missing several stars, it also has to be said that Portadown had a number of injured players sitting in the grandstand.

Portadown were really up for this game and they signalled their intentions with a number of early attacks in which Andrew Sproule and Richard Lecky were prominent.

Blues keeper Stuart Addis had to be alert to deal with an early threat from McCutcheon, but on 10 minutes Linfield came closest to scoring.

John Martin got on the end of a cross from Damien Curran and his header had goal written all over it only for Neil Armstrong to bring off a brilliant diving save.

On 23 minutes a shot by Matthew Doherty whizzed past the upright as Linfield continued to press forward. But two minutes later they were very fortunate not to concede a penalty kick.

John Convery was powering through the visiting defence when he was upended by Conor Hagan. It was have been a hair-line decision, but referee Mark Courtney decided the infringement was just outside the box, and McCutcheon's powerful strike from the free-kick was charged down by the Linfield defence.

The Ports grabbed the all-important breakthrough goal in 43 minutes with a super strike by Boyle.