Northern Ireland extended their unbeaten start to the Nations League campaign in Monday’s 0-0 draw with Hungary, but the main test of this new-look extended international window is just beginning.

Under the old calendar, Michael O’Neill and his team would now be heading home from an encouraging start with four points from two matches, even if tinged with the knowledge that a bit more killer-instinct would have seen them beat Hungary at Windsor Park.

But with two international windows now compressed into one, Northern Ireland have one extra recovery day before they head to Trnava, Slovakia, for Friday’s match against Ukraine – now a top-of-the-table clash in Group B2.

O’Neill has been clear in his view that compacting two windows into one has a greater impact on smaller nations whose limited resources are severely stretched in playing four games in 11 days, and the next two games may provide the proof.

placeholder image — Northern Ireland manager Michael O'Neill reacts on the touchline during the UEFA Nations League draw with Hungary. (Photo by Liam McBurney/PA Wire)

“I think we may see when we get to game three and game four, maybe the depth of squad will be more of a factor,” O’Neill said. “I think Ukraine made a lot of changes to their team (in Monday’s 0-0 draw in Georgia). I don’t think we’re in a position to be able to do that at this minute in time. So it will be challenging over the next two games.”

Northern Ireland have also been dealt a tough hand with the schedule, with Monday’s match coming on the back of a 5,000-mile round trip to Georgia. Now they travel to play Ukraine before returning to Belfast to face Georgia again next Monday.

“Tiredness will be a big factor in it,” O’Neill said. “Logistics are a big factor as well in terms of your travel. We’ve seen teams like Georgia have had two home games in a row, so things like that create a bit of an imbalance.

“I know it’s difficult to get the fixtures all right, (but) the only thing I would like to see is we have an extra day’s recovery now going into the third game, I would like to see the recovery periods between the games be consistent.”

O’Neill made only one change on Monday from the side that won 1-0 in Tbilisi on Friday, with Ruairi McConville replacing the injured Dan Ballard and delivering a strong performance in central defence.

“Our squad’s young and I don’t want to put too many young players on the pitch in a game where they’re untried, they’re untested at that level,” O’Neill added.

“It’s a very physical game and we want to bring the younger players in to give them the best chance to be able to do well and build their confidence and to build their reputation.

“That’s challenging for us at this minute in time. We have more experience in our options and substitutions in our back-line – we could have brought in Terry Devlin, we could have brought Paddy McNair in.

“When we look at the top end of the pitch, we’re looking at much younger players – Kieran Morrison, Ceadach O’Neill, Braiden Graham – so we don’t have the same options in terms of what we can do at the top end of the pitch.”