Arsenal completely failed to learn the lessons of the last-minute goal conceded against AZ Alkmaar and threw away a two-goal lead against West Ham at Upton Park yesterday. It was an exasperating outcome which meant that rather than finishing the day within striking distance of the top of the table, the Gunners had to content themselves with lurking in third, five points off the pace with a game in hand.

Yesterday's performance was arguably the weakest overall display the team has turned in this season. Even when they lost to United and City, they showed a good deal more spark and purpose in those matches than they mustered at the Boleyn Ground.

The Gunners did not have to do very much to get themselves two-nil up at the break - both strikes owed as much to inept West Ham defending as they did Arsenal's attacking menace. Just after the quarter of an hour mark, Robin Van Persie fully punished Robert Green's weak palm out from a Bacery Sagna cross and William Gallas rose above an earthbound Hammers defence to head the second in the 37th minute.

The Hammers looked a beaten side at the break and it seemed that Arsene Wenger’s team only had to maintain their discipline to secure the points. As it was, they went completely off the boil after the re-start and their second half display was pathetically lackadaisical.

A couple of substitutions breathed a little bit of life into the home team's effort but they didn't particularly look any more likely to pull a goal back. Then, in the 74th minute, Vito Mannone haplessly parried a Diamanti free-kick right back into the danger area and Carlton Cole slotted home the loose ball. Six minutes later Alex Song conceded a penalty and Diamanti struck the equaliser from the spot.

Even though the team had looked below par throughout the match, to have thrown away a two-goal advantage was bitterly disappointing. Much focus falls on the current goalkeeping situation at the club as, yet again, a Mannone mistake cost the team a goal whilst Manuel Almunia looked on from the sidelines. All the credit the young Italian had accrued with his saves against Fulham has now been used up after errors against Blackburn, Birmingham and now West Ham have all led to goals.

You have to feel slightly sorry for the young man. He is extremely inexperienced and has been thrown in at the deep end in one of the most competitive leagues in the world. It is inevitable that he will make mistakes. These, though, are errors that Arsenal cannot afford if they are to mount a serious challenge for the title this season. Whatever is going on in the goalkeeping department, it is a situation that Arsene Wenger has to address and sort out quickly and decisively.

After his performances in the last few games, persisting with Mannone surely cannot remain an option. Either Almunia has to be reinstated or Fabianski, who has now returned from injury, put in the side. It would seem that the Pole is likely to start against Liverpool in the Carling Cup on Wednesday, so it will be interesting to see who the manager plumps for come Saturday and the visit of Spurs.

In the longer term, if Almunia is now completely out of favour, one also has to question whether Fabianski is really experienced enough to handle a title challenge. It may be that Wenger will have to buy a goalkeeper in the January transfer window because Arsenal really cannot afford to be breaking in rookie goalkeepers in a year when they are supposed to be proving they are genuine contenders to actually win the Premier League.

Though a draw at West Ham is not a total disaster when all is said and done, it was still two points dropped rather than one earned and a display that left Arsenal supporters once again tearing their hair out. In the 24 hours since the final whistle, the manager and some players have been coming out in the press saying that the West Ham game taught them a lesson about being ruthless. But wasn’t that the same lesson they were given last Wednesday in Holland? How many times do they have to throw away leads before this stuff starts to sink in?

One thing that is absolutely certain is that they will have to raise their game, their work-rate and their attitude a good few degrees before the visit of Spurs on Saturday. If they stroll around in a North London derby the way they did at times yesterday in East London, they are going to find themselves on the wrong end of a beating at the hands of their bitterest rivals.

Spurs have completely revitalised themselves under Harry Redknapp over the past twelve months and, on paper, next Saturday’s clash will be one of the most even in terms of current form for some years. They will be coming to Ashburton Grove with a very big point to prove and Arsene Wenger needs to get the players as keyed up as the supporters will be. This is not a run-of-the-mill fixture. This is a match that determines the joy or misery of both sets of supporters for the next few months. This is the North London derby and the players need to approach it with the same passion as the fans.

Before that, there is the not insignificant matter of taking on Liverpool in the Carling Cup at the Grove on Wednesday. Clearly, the tie could be decided by the respective strength of the teams that Arsene Wenger and Rafa Benitez put out. As usual, the Frenchman is likely to give chances to second-string players and youngsters and we can only hope that we have another one of those nights where the kids turn in the sort of inspirational performance that they seem to regularly summon in this competition.

Carling Cup nights at Ashburton Grove have been highly enjoyable over the past few seasons and hopefully Wednesday night will be no exception.