Just as it seemed that Arsenal had done enough to win an untidy match against AZ Alkmaar in Holland on Tuesday night, hesitant defending from a free kick allowed the Dutch side the opportunity grab a late equaliser. The Gunners had to settle for a point when they really ought to have taken three but it was an outcome that should not do any serious damage to their qualification hopes or, indeed, their chances of winning the group.

Though Arsene Wenger’s men dominated the ninety minutes and, for the most part, looked good value for a win, the late concession of a goal ought to serve as a timely reminder that, for all their sumptuous attacking play, defensive miserliness is just as important a facet for any successful team. The beautiful simplicity of Cesc Fabregas's goal underlined the team’s brilliance going forward but this was counter-balanced by the team's failure to defend a route-one set-piece at the death. From a speculative punt into the area, Granziano Pelle was allowed an unchallenged header and he nodded the ball into the path of Mendes da Silva who simply ran behind the static Alex Song to volley home. Though the players might have been looking around at each other after the ball hit the net, replays showed a catalogue of collective and individual errors.

Defensive lapses such as these have rather become a fact of life with this current Arsenal team. Whilst such mistakes can be forgiven and overlooked when three or four are being scored at the other end, there will be times when the team find themselves defending a one-nil lead and they need to be able to close out games defensively, particularly away from Ashburton Grove. They managed to do this at Fulham a few weeks ago but it took two or three exceptional saves from Vito Mannone to get them over the line. The Gunners have, in fact, only managed five clean sheets in fourteen matches in all competitions so far this season and this is a ratio that needs to be improved upon if they are to seriously challenge for silverware.

Though many have pointed to the lack of height across the back four this season, last night's error was more to do with lack of organisation and concentration - and those are things that can be worked on and put right. Improvements will have to be made because teams like Stoke and Bolton, who often make great capital out of difficult-to-defend set-pieces, will have looked at the defensive shambles that the AZ freekick induced and seen a potentially cheap way of nicking goals against Arsenal.

The team does have some experienced defenders who ought to be capable of marshalling others and dealing with situations like last night's, but another factor to consider is the current uncertainty over the position of goalkeeper which must be undermining the confidence of the back four. With Manuel Almunia now seemingly recovered from his alleged chest infection and being kept on the bench by Vito Mannone - who is still an extremely raw rookie - one has to wonder whether the Spaniard has irrevocably fallen out of favour with the manager or whether this is just a temporary state of affairs.

Either way, some clarity is definitely needed because a revolving-door selection policy in such a crucial position, which will only be confused further by the imminent availability of Lucasz Fabianski following his return to action in the Reserves last night, will do nothing for the confidence and lines of communication amongst the defence in the long run. If the team are going to push for honours the season they have to be solid and consistent at the back and that starts with the goalkeeper.

Looking at the positives from last night, the Gunners bossed most of the match and created the far better chances. They also had what looked a stonewall claim for a penalty turned down in the second half when Carlos Vela was felled in the area. Surprisingly, the referee waved the game on. Had the spot-kick been awarded and converted there would have been no way back for AZ. With three matches still to play in the group phase of the Champions League, two of which are at home, it would a catastrophe if Arsenal did not qualify from this position and, in reality, they still look favourites to top the table come December.

Coming up over the next ten days are West Ham away and Spurs at home in the Premier League and, in between, the youngsters and second-stringers will take on an embattled Liverpool in the Carling Cup next Wednesday. Hopefully, the events of last night’s injury-time will have served as a sharp lesson about maintaining concentration until the final whistle and re-focussed the players’ minds ahead of the two London derbies coming up. Last season, a 4-2 lead against Tottenham was chucked away in injury time at the Grove and a repeat of that would be a good deal less easy to bear than last night’s disappointing finish in Holland.