Ireland, after those games against Azerbaijan (3-0), Qatar (4-0) and Portugal (0-0) are on a run of three successive clean sheets. It’s not quite an era-defining run and two of those clean sheets were against poor, shot-shy sides in Azerbaijan and Qatar. The team has been, through the peaks and troughs of latter years, proven itself capable of defending.

There were four successive clean sheets, between the back end of the Martin O’Neill era and the start of the Mick McCarthy reign (against Northern Ireland, Denmark, Gibraltar and Georgia). O’Neill also twice had runs of three successive clean sheets (Gibraltar, Georgia, Germany, then Moldova, Wales, Denmark).

It will be hard for any Irish side, ever, to beat the run under Giovanni Trapattoni when his side did not concede a goal in eight games (against Northern Ireland, Slovakia, Macedonia, Italy, Croatia, Slovakia, Russia and Andorra).

Trap liked winning games but he loved keeping clean sheets, treasuring each one like a grandchild.

Under Kenny, the team let in two goals in his first two games (Bulgaria, Finland), then saw out 2020 with a scoreless draw at home to Bulgaria. But in 2021, the goals flowed, and not the way Kenny wanted: 2-3 (Serbia), 0-1 (Luxembourg), 1-1 (Qatar), and 4-1 (Andorra). The goals were conceded at short range from poorly defended set-pieces and from distance, with Gerson Rodrigues given the freedom of Dublin 4 to fire past Gavin Bazunu.

There was a lot of finger-pointing after those goals went in, and while the focus falls on the ’keeper and the men immediately in front of him, that Irish back line was far too often left exposed by midfield. Young players struggled – Dara O’Shea had only one clean sheet in his first five games.

Since then, Josh Cullen has blossomed into a midfielder of real international class, with more of an awareness of what’s needed, while Jeff Hendrick has gone through a rebirth with Ireland, showing none of the ring-rustiness which is inevitable given his lack of game-time at club level.

Bazunu also looks to be more at ease compared to those early days. In defence of the Firhouse man, he was a teenager, playing for a Rochdale side in danger of relegation to England’s fourth tier, when he came into the side. Azerbaijan last month was his first clean sheet in 90 minutes – he only played half of the scoreless draw with Hungary.

“We are improving as a team overall, we still need to improve again, there are areas where we need to improve, two of the expensive goals that we conceded at home were long-range efforts, from 25/30 yards, collectively the players are getting better, getting better as a team and everyone is playing a part,” Kenny says when asked about the defensive record, pointing out that the defensive unit had, due to injury, suspension and Covid issues, rarely been a settled one, until now.  

“We’ve had different players playing, everyone has done well, Séamus (Coleman) has been missing with injury, Shane Duffy’s form has been transformed, in my opinion John Egan could play in the Champions League, he should be playing in the Champions League.”

The midfield now offers more of a blanket of protection, but it’s the mean streak from Kenny’s defenders which gives the team steel. The three-man axis of Coleman, Duffy and Egan put a cordon in front of goal which Portugal struggled to cope with, while wide men Enda Stevens and Matt Doherty worked on the attacking side as well as defensive duties.

This is also a defence which will, when fitness permits, have Dara O’Shea and Andrew Omobamidele available, with £17m man Nathan Collins also a steady hand and a cool head at the back. Of course the record is put on the line in Luxembourg tomorrow. They have scored in five of their last seven games, and hit three in Baku, as Ireland did.

But Luxembourg is not an impregnable fortress: Austria scored three times there, Liechtenstein got two goals there. Ireland will need more of a clinical edge to win the game.

Yet it’s denying a goal or goals to Luxembourg which will show how much Ireland’s players have learned in the last 19 months. A clean sheet won’t win any more points but would do wonders for Bazunu’s confidence.