TROY PARROTT STUCK out his foot and scraped his studs on the top of the ball in anticipation of glory.

The chaos and life-affirming sensation that followed would not have been possible without Liam Scales’ leap of faith in Budapest.

Those two acts ensured the Republic of Ireland are building towards what they hope will be the first of two World Cup play-offs later this month.

Boss Heimir Hallgrímsson and his assistants, John O’Shea and Paddy McCarthy, have got their preparation in place for a semi-final clash with Czechia in Prague. There have already been fraught moments in the build up to 26 March and there will be more to come until Ireland take to the field.

In the first of a three-part series examining options available and problems to be solved, we look at how Ireland’s foundations in defence are close to being set.

Scales knew two things in that moment as he rose above two Hungarian defenders. He knew it could lead to something special and that he would not be available for selection in the first game of any play-off.

His yellow card – after being booked in the 2-0 win against Portugal a few days earlier – means he is one of two players suspended. Festy Ebosele is the other and while he has barely kicked a ball for Istanbul Basaksehir, and hoped to secure a loan move in January, his absence will also be felt given his ball-carrying ability should Ireland be chasing the game late on or in need of someone capable of providing relief.

Hallgrímsson’s reign can now be stripped back to everything post-Armenia, when a sobering defeat in Yerevan provided a kind of caustic clarity that helped turn things around so dramatically.

The Ireland boss’ Come to Jesus moment was more like a Come to Coleman, a realisation that so long as he is fit he will start in what is now essentially a back five.

It is inconceivable at this point that he is overlooked by Hallgrímsson again, especially after it became so glaringly obvious how much stronger he makes this team. That is not just through his on-field leadership but also the quality he possesses, all of which filters through to those around him, spreading confidence and comfort.

Captain Nathan Collins may have found himself out of the Brentford starting XI for five of the last six Premier League games but Keith Andrews put him back in for the 0-0 draw away to Bournemouth in midweek.

There may still be question marks over his decision making and concentration levels but he didn’t shy away from any responsibility during the group campaign.

Collins made the most clearances (34), blocks (nine) and even had the most shots off target (six) of any Irish player.

Fourteen of the 17 goals Czechia scored to get to this point were inside the box so protecting it is paramount.

John Egan has got everything and more from his move to Hull City but is that enough to dislodge Collins at such a crucial point?

Jake O’Brien is on the cusp of reaching 50 Premier League appearances with Everton and he looks every inch a player at that level – not to mention the long throw now in his repertoire.

Dara O’Shea has been going about his business with the usual emphatic diligence at Ipswich Town as they remain in the mix for automatic promotion back to the Premier League.

A breakdown of Ireland’s build-up play during the qualifiers also highlights another key aspect of his importance.

No player made more passes (121) in the opposition half than O’Shea and while that only serves to reinforce the feeling of a lack of control and creativity in midfield, it also highlights his front footed approach, adhering to the doctrine of Hallgrímsson to lead by ‘action and reaction’.

It is Scales’ absence that offers the most obvious opportunity for a change.

Robbie Brady’s return to fitness with Preston after ankle surgery in the summer is timely, while Matt Doherty will be in the mix.

Brady, of course, is the reigning FAI senior men’s player of the year, and his ability to deliver with set pieces and free play crosses is a key reason for that. Not to mention an important weapon for Ireland to use.

Of the eight goals Czechia conceded during qualification – five of which came in a single defeat away to Croatia – all were inside the box.

Equally, Ryan Manning will view that as reason why he is primed to get the nod. No Ireland player attempted more tackles (nine) than the Southampton man or made more interceptions (eight) but his 35 crosses were also the most attempted by an Irish player.

With Caoimhín Kelleher in goal, Coleman at right back, and O’Brien, Collins and O’Shea in situ, Manning would appear to be in the strongest position to get the nod.

Probable defence:

Seamus Coleman, Jake O’Brien, Nathan Collins, Dara O’Shea, Ryan Manning.