"We know that when you go to Porto you need a solid defensive performance". So said Arsene Wenger following last week's victory over Liverpool. What we actually got was a horror show of a performance from Lukasz Fabianski that saw the Gunners go down 2-1 in a match that they really ought to have taken a result away from.

In the 24 hours since the final whistle Porto's goals have been shown innumerable times on the television and they don’t get any easier to watch with each viewing. The first saw Gael Clichy skinned on the right wing and Fabianski, with no one near him and caught in a bad position, fumble the resultant cross into the net. The second was a comedy of errors between Sol Campbell and the hapless Polish keeper, except there really wasn't anything remotely funny about it.

The incident that led to the freekick was only one half of the story. Sol Campbell may have confused the young goalkeeper by touching it back to him but if there was any doubt in his mind Fabianski should have just put his foot through the ball and cleared it. His error was then compounded by simply handing the ball back to the referee to allow Porto to take a quick freekick. A more switched-on keeper would have held the ball until his defence got back and taken a yellow card for it if necessary. It would be kind to say that his handling of the situation was naïve and inexperienced. More accurately, it was incompetent and unprofessional.

Fabianski and Campbell ©Getty Images

The sad thing is that one could hardly call last night’s calamities a one-off. It has been a generally held opinion on this page over the past couple years that Fabianski is a decent instinctive shot-stopper. However, the moment he has to think about his game, he is left wanting time and again. He flaps, he panics, his decision-making is usually rash and, more often than not, dreadful. Last night brought into sharp focus the flaws in his make up that seem to surface match after match after match and he fails to instil much confidence when coming in to replace Manuel Almunia.

In his post-match interview, Arsene Wenger refused to criticise his goalkeeper and instead turned his attentions to the referee for allowing the second goal to stand. Rarely though has the manager looked less authoritative in his criticism. Porto were guilty of nothing more than quick thinking and exploiting a dozing Arsenal defence. It was the sort of thing that Thierry Henry had the presence of mind to try on regular occasions in the past. There were no complaints from Arsenal quarters then and so there can be very little to moan about in this instance. At least, Cesc Fabregas had the honesty to admit that both goals were due to schoolboy errors.

In fairness to Wenger, he has always devoutly refused to censure his players in public. When he tells an interviewer that he hasn’t seen an incident, what he really means is: "I don’t want to talk about that". Similarly, one senses his slating of the match referee was more a smokescreen in order to divert attention away from Fabianski’s performance. Privately though, the manager must surely be as irritated as most fans are with the two moments of ineptitude that cost the Gunners the chance of coming away with a more creditable first-leg result.

On the brighter side though, despite the annoyance at the manner of the defeat, there is still plenty to be optimistic about for the second leg. Arsenal weren’t at their best all over the pitch last night but still looked more than a match for Porto. Take the ruinous goalkeeping errors out of the equation and the Gunners looked good value to take at least a draw, and so they can approach the return leg at Ashburton Grove with a certain amount of confidence that they will be able overturn the deficit.

To do so though, they will have to ensure they defend far better and try to control the tempo of the match a lot more effectively. Last night, the game was an end-to-end affair for virtually the entire ninety minutes. There was talk from the manager about the team taking a more conservative approach away from home in this tie but there was little evidence of that. The match was far too open. It might have been a good one for the neutrals to watch but wasn’t one for purists or Arsenal fans.

In the wake of Fabianski’s disastrous night, the debate about the goalkeeping situation at the club has heated up again. At the start of the season, there was not much talk about it being a particular weakness of the squad but as the season got underway so did the concerns about that position in the team and the discussion has not stopped since.

Manuel Almunia has taken plenty of criticism this season and his extended absence in the early part of the campaign did raise some anxieties that his head might not be in the right place to handle the task. With Fabianski then injured, Vito Mannone stepped in. He covered himself in glory with a string of important saves that helped notch a hard-fought victory at Craven Cottage against Fulham. He then systematically undid all his good work in subsequent games when errors that exposed his inexperience cost several goals. Almunia came back and has maintained his place despite worries about his form. The few appearances that Fabianski has made have shown little to suggest that he is ready to take the Spaniard’s place as first-choice keeper.

With the transfer window shut now until the summer, Arsene Wenger and Arsenal supporters are just going to have to make the best of what they have got until May. For my money, Almunia is still the best option as neither Fabianski nor Mannone inspire much confidence and lack the individual authority and composure to push themselves into the number one slot. Some might see the Spaniard as the best of a bad job but there is not much in the way of an alternative at the moment.

It will be interesting to see what the manager does do in the summer though and which of his goalkeepers he decides to keep faith with. He will, of course, have the option of buying a new recruit but there is another alternative. Wojciech Szczesny who is currently on loan at Brentford has been earning himself rave reviews and has endeared himself to the fans there. On the evidence of his performances over in West London this season, he is as entitled to the same sort of chances that have been given to Mannone and Fabianski when he returns to Arsenal.

After watching last night’s episode, it was hard not to think back to Arsenal’s run to the Champions League Final in 2006 and recall what a massive part Jens Lehmann played in getting them there. He was superb in every round and his penalty save in the semi-final against Villareal was as important as any of the goals scored en route. It was a tragedy for him that he was sent off so early in the final after being drawn into bringing down Samuel E’Eto as the last man. That did not stop him from being named goalkeeper of the tournament after not conceding a goal in over 800 minutes of football and helping the Gunners break a record for consecutive clean sheets in the Champions League.

Almunia, Fabianski and Mannone need to look to that level of performance, professionalism and, sometimes, gamesmanship to see what it takes from a goalkeeping point of view to move the club to the brink of a truly major achievement.