If Arsenal had a defence as impassable as their mental block they would never lose another match. They continue to be the supreme obstacle to themselves. There were several chances for the visitors in this FA Cup quarter-final and Edwin van der Sar was outstanding in response but the finishing was never accurate enough to leave the goalkeeper helpless. Targets of one sort or another are also being missed entirely.
While winning the Carling Cup might have been just a small piece of encouragement to Arsenal, defeat in the final has done harm. A malfunction in defence helped Birmingham City to make off with a trophy they deserved, if only because they rose to the occasion while Arsenal had the equivocal look of men with far grander matters on their mind. Those distractions are now being ripped from them.
The club is left with stark circumstances. In the space of a fortnight the chase for four trophies has shrunk to the pursuit of the Premier League alone. Arsène Wenger will surely present that as an opportunity to land a fine prize while others are distracted by further honours. Arsenal are in this situation, though, because they cannot help but bring trouble upon themselves.
They were, for instance, the sole English club not to win their Champions League group. The worst possible penalty was imposed when they were then pitted against Barcelona, who eliminated them last Tuesday, but a trying contest of some sort had been inevitable for the runners-up in a group where they were beaten at Shakhtar Donetsk and Braga.
Wenger understood fully that the FA Cup tie mattered, if only for the potential fillip enjoyed by anyone who beats Manchester United, but too little was done to test the composure of opponents who had just fallen to Chelsea and Liverpool. Unlike Sir Alex Ferguson, Wenger picked the most potent line-up available. The hosts, all the same, were smart in the shaping of a selection that saved several people for the return leg of the Champions League tie with Marseille on Tuesday while still presenting problems to Arsenal.
In the Da Silva twins, for instance, United had men with a lot of energy to apply against visitors drained by their defeat at Camp Nou. The Brazilians are full-backs and John O'Shea is also regarded as such nowadays, yet all of them were accommodated in an implausibly effective midfield. Eminent substitutes were barely needed and when Paul Scholes did enter the match he deserved to be sent off, rather than only booked by Chris Foy, for uncontrolled tackling that showed an indifference to the safety of opponents.
Nonetheless, Arsenal have to be angry with themselves primarily. Apart from the amble to a 5-0 win over the League One club Leyton Orient in their FA Cup fifth-round replay, the team has not scored more than a single goal in any game since 16 February. Wenger has to reverse the trend and do so when issues that he cannot affect are taking a toll. A recalcitrant achilles problem means that the most recent outing in the Arsenal defence for the influential Thomas Vermaelen took place on 28 August.
His unavailability helped bring Johan Djourou to the fore but the Switzerland international dislocated his shoulder in the closing stages at Old Trafford when his team-mate Bacary Sagna collided with him and will not play again this season. In the specific context of this FA Cup tie Arsenal had, in theory, a better-balanced side than United but Abou Diaby, in a key role behind Robin van Persie, barely made a contribution.
For that matter Van Persie himself dwindled after United had taken the lead. With 27 minutes gone, Wayne Rooney crossed and, although Manuel Almunia parried away the header from Javier Hernández, the loose ball was turned in by Fábio da Silva. The outcome was settled four minutes into the second half when Djourou put himself in the path of a Hernández shot, only for Rooney to head home the loose ball.
Arsenal, for their part, never seemed like a team that would come up with the sort of pass or shot that would lead to a certain goal. The match was allowed to turn into a therapeutic exercise for United, who might have had a niggling fear that this sort of tie had the potential to leave them with another loss. The game was even soothing enough for Antonio Valencia to be brought on for his first appearance since breaking his ankle on 14 September.
It would have been galling for Arsenal to find themselves part of the winger's rehab programme. Many aspects could have been happier for Wenger, who had scant cover in front of his defence even though Jack Wilshere started moves with much style from that area. The manager resorted to exaggeration when portraying the present situation as an achievement in its own right: "If I listened to everybody, it is a miracle that we are playing for the title with 10 games to go. Nobody in England believed we could even fight for the top four. The position we are in deserves a lot of credit."
Wenger could not entirely conceal despondency about his casualties: "We would like Alex Song back, we would like Cesc Fàbregas back and now we have to cope without Djourou, who is an outstanding player." Above all it will, however, be Arsenal's capacity to recover from a bad result like this that determines their fate in the Premier League.