Brian Kerr: Ireland can't allow this chance to pass them by
O'Neill must get his selection right if his side are to set the tone and secure spot in Russia
Ireland's World Cup destiny will be decided tonight. Their approach must be dictated by the choices they make - it cannot be left to chance.
Denmark's creative possibilities in Copenhagen were largely destroyed by Ireland. Now the emphasis in Dublin switches to Martin O'Neill's men and whether they can display an intention to create themselves.
Clearly more determined to protect their own final third on Saturday, Ireland will now be expected by a packed Aviva to have greater designs on occupying the Danish final third.
This is not Germany; the crowd will be nervous if Denmark hog possession, as similar sides like Wales and Austria managed to do earlier in this competition.
We will need to put more pressure on their back four in what is deemed the normal Irish style; sitting back and allowing the opposition to be so comfortable in possession in their own half is not the usual Irish way.
Neither is the absence of an aspiration to retain possession; every restart on Saturday went long and it was no coincidence that Ireland's two scoring chances derived from the sole occasions when they strung four positive passes together.
This is not about passing for the sake of it, but passing with a purpose. O'Neill has declared his team will play with purpose this evening.
Saying it in a press conference is one thing; translating it on to the pitch with the correctly selected team, receiving clearly communicated instruction, quite another.
This change of approach will also require fresh energy, essential with the two games so close together. Recent experiences in Dublin can offer some guidance but not clarity.
Against Moldova, when Robbie Brady was suspended, Ireland played 4-4-2 in a match we had to win with Shane Long and Daryl Murphy up front, with Callum O'Dowda on the left of a midfield diamond and Hoolahan at the top of it, and an early goal from Murphy gave Ireland control.
The Serbian selection was similar and Hoolahan performed well that night as Ireland matched them attack for attack until his withdrawal prompted a route-one approach.
I suspect, though, tonight's team will lean more towards caution than adventure because the stakes are so high and the tie so finely balanced. Hoolahan won't start, though I would like him to.
The freshness will be provided by the returning David Meyler, whose influence has been so key of late.
The presumption is that it will be at O'Dowda's expense, even if he did well on Saturday despite being starved of supply; hence, the midfield will mirror that which played in Cardiff.
Shane Long may start for Daryl Murphy, who expended 74 minutes of exhaustive running on Saturday.
Long's pace may allow him to hustle harder and may be more unsettling when the opposition centre-halves are on the ball.
James McClean will again be wide on the left, Brady wide to the right and then three in the middle - Meyler sitting, with Harry Arter and Jeff Hendrick offering protection on either side.
In contrast to Cardiff though, we need one of these midfielders to be closer to Long; akin to Hendrick's harrying of Ashley Williams in the final third, with two Irish midfielders arriving in the penalty area to eventually produce the winning goal.
This was a picture we never saw in Copenhagen. There was no intention to pass to a colleague or provide support.
Ireland's ability to retain the ball would, in my mind, be better served in a 4-4-2 with Hoolahan playing just off Long.
Any of the games where we have had a distinct pattern of play, which has created chances and also expanded the positive elements of the rest of the team's positive attributes, have coincided with his presence.
Unfortunately, none of the other midfield players have been able to have this effect on the team when Hoolahan is absent, which is baffling considering they are all playing in passing teams who regularly encounter superior opponents in the Premier League.
And the fact that Roy Keane, for one, can supervise a situation in Copenhagen when the first instinct of midfielders is to hoof the ball anywhere, rather than attempt to locate a colleague, is equally surprising.
Retaining the ball allows a team to build pressure on opponents' defensive shape but also deny them the opportunity to put pressure on you.
Where does the passing start?
More confident and better-directed teams start with the full-backs or centre-backs but Ireland don't do this.
A midfielder can receive it from the defence, retain possession and then try to create something from there. Arter attempted to do this initially on Saturday but his options were starkly limited.
Or else you can press to win it back in the middle of the pitch and then have an intention to pass. Ireland's first instinct, alas, was to kick it away as far as possible.
When any long balls found Murphy, everyone was too far away to support him; apart from sporadic raids from McClean and Cyrus Christie's solo efforts in the wide spaces but it was obvious even in those instances that there was nobody offering support.
Of course, now the danger is that Ireland's intent may allow Christian Eriksen to find the space from where he delivered three shots on goal on Saturday.
Having said that, we've seen everything Denmark have but have they seen everything from us? I think they've shown their hand. Their style was as obvious as the absence of any from Ireland.
While it is difficult to assess the Danish options, the ineffectiveness of their front players on Saturday offers encouragement that Eriksen remains their only real threat.
They have used all their combinations up front; Yussuf Poulsen may start. Their midfield and defence is likely to be unchanged too.
Andreas Cornelius played close to Nicolai Jorgensen on the right side, allowing Peter Ankersen to threaten on the right while the fitful Pione Sisto also tried to drag Christie centrally to allow Jens Stryger Larsen overlap on the left.
William Kvist often drops in with the centre-backs to receive, the full-backs push on high and wide and they tried the diagonal ball to the overlapping full-backs, or long balls to the front men.
Our three men in front of the centre-halves stopped them playing through the middle, forcing them to play more longer balls than they wanted to.
Eriksen often cut a frustrated figure by the lack of awareness or ability of the support crew to play him the correct pass or read his intentions.
Christie and McClean made brilliant interceptions to prevent the critical pass behind their back four; Christie blocked a couple in the first half and I counted three by McClean in the second.
But maybe the quality of the grass favoured destroyers over creators in what developed into a pitched battle.
Even without possession, the Irish team looked comfortable under pressure.
The massive work-rate and discipline of the five midfielders, combined with Darren Randolph's sharp reflexes, allowed us to come away with a result that leaves them in control of the tie, considering the second leg is at home.
While the defensive performances were admirable, a failure to maintain possession for any extended periods in the game meant Ireland were almost non-existent as an attacking unit. And that increases the pressure on the defence.
O'Neill has overseen some great days over his term. His team this evening must know that composure and courage on the ball can be a pathway to Russia which these Irish players are capable of.
An alternative route-one might get us there but let's do it with a bit of style.