Northern Ireland manager Michael McArdle says his side will have “one last swing” at trying to reach a first World Cup as they look to overcome a four-goal play-off deficit in Portugal.

Portugal backed up their favourite’s tag as they ran out 4-0 winners in the first leg at Inver Park on Friday night.

That result led to McArdle saying that the hopes of a first World Cup had gone from “improbable to impossible”.

But, speaking in Portugal ahead of Tuesday’s second leg, which will be shown on BBC iPlayer, the 48-year-old believes that a strong start can turn the momentum towards his side.

“We’re always positive, and from that perspective it’s another opportunity for us to learn and put ourselves toe-to-toe with them,” McArdle told BBC Sport NI’s Faith Harper in Portiamo.

“Who knows what the game throws up tomorrow night.

“If we end up in front first or how the game goes, it could turn back from impossible to improbable again, and go in the other direction.”

McArdle handed debuts to Linfield defender Jane McMaster, Sparta Prague forward Kess Elmore, who made a lively appearance off the bench, and 16-year-old Cliftonville midfielder Charlotte Havern.

Aside from striker Cora Chambers, who was sent off in the closing stages of the loss on Friday, Northern Ireland have a full compliment of players to pick from for the second leg.

Telma Encarnacao scored an early opener in Larne before before Jessica Silva doubled the lead and Rebecca Holloway scored an own goal inside the opening half hour.

Northern Ireland improved after the restart, and looked the better side after Catarina Amado’s red card, but could not find a goal their pressure deserved, and the visitors capitalised as Fatima Pinto scored a speculative, long-range fourth.

McArdle knows where his side need to improve heading into the second leg.

He pointed to how Portugal were able to exploit the gaps between the centre-backs and the inexperienced full-back duo of McMaster and 19-year-old Emily Cassap, and how his own team could not convert their pressure into goals.

“The immediate reflection was misfortune with the scoreline, and how it was a bit harsh,” he said.

“Reflection-wise we still feel that way, however there’s areas that we need to improve upon before the game.

“There were some positives but obviously the scoreline is the scoreline.”

Even if Northern Ireland can pull of a miracle in Portimao, they would still face an uphill task to reach a first-ever World Cup.

Iceland, who are 4-0 up against Croatia from their first leg, would likely be the second-round play-off opponents and, even then, Northern Ireland would probably then face an additional inter-confederation play-off due to their Uefa ranking.

But McArdle knows he is not just working towards the finals in Brazil next summer, but further ahead.

The Scot feels he has seen “lots of progress” in his six months in charge, and feels that will only improve as he continues to get to know his squad.

“You’ve seen that with the new players, the amount of debutants and the amount of youth players that come into the squad over the three camps I’ve been involved now.

“We’re now in a really strong place, and from the next window onwards we’ll to start prepare and focus on trying to qualify for the Euros.

“That’ll be the most important piece after Tuesday, but we’ll have one last swing and see where it goes.”