Arsenal moved from a state of slight concern into discernible worry after their second moribund display in five days, which resulted in a deserved loss to the Germans, Schalke. To paraphrase the sporting aphorism, Arsenal lost 2-0, and were lucky to get nil.

Weakness in possession

Despite dominating the early stages, at one point having 74% of possession, Arsenal seemed to lack any clear idea of how to break Schalke down. The German outfit were well organised, swiftly getting all 11 players behind the ball, and looking to close down Santi Cazorla and Mikel Arteta at every opportunity.

Arsenal's tactics often led to passing the ball sideways without any penetration. Their other attacking gambit was to hit aimless long balls from deep into the channels for Gervinho to chase. With Arsene Wenger in the stands, serving the final match of his touchline ban, Steve Bould was watching the team play with a style at times that was not dissimilar from the Arsenal side he used to play in.

Lack of Verticality

This was the type of match where Theo Walcott would likely have thrived. His directness when bursting forward would have given Arsenal a clear threat, and could have been a regular target for Cazorla, Arteta and Aaron Ramsey to play through-balls to. This is something that's known as "verticality".

Passing sideways and keeping the ball is important, but to cut through your opposition, you often need someone who can operate from back to front, as well as side to side. It was what Freddie Ljungberg did for Arsenal circa 2001-2005, and is best embodied by Pedro at Barcelona. When Xavi and Iniesta are anaesthetising the opposition with their tiki-taka, Pedro will often make a forward dash - a great example of this is his goal against Manchester United in the 2011 Champions League final.

The reason why I'm digressing is to illustrate a key area in which Arsenal were short. With Walcott and Alex-Oxlade Chamberlain injured, Gervinho playing down the middle, and Aaron Ramsey out of sorts, everything was played in front of the Schalke backline. As a result, the first shot on target didn't come until stoppage-time, by which point the contest was already over.

The Left-Hand Side

Schalke had clearly identified Andre Santos as the weak link in the Gunners defence. So far this season, the Brazilian has been a poor deputy for the crocked Kieran Gibbs, and struggled against the Peruvian wide-man, Jefferson Farfan. If Farfan's had taken more advantage of the space he was given, the game would have been over long before he set up Ibrahim Afellay to seal the match.

Santos had a wretched match, often looking vulnerable against Farfan, as well as Schalke's right-back, Atsudo Uchida. He was sloppy when on the ball, and failed to help the back-four stay in a solid line. It was his solipsistic ball-watching that allowed Klaus Jan-Huntelaar to stay onside to score the game's opener.

In Santos' defence, he wasn't helped by being given little to no defensive cover. Lukas Podolski, normally so diligent in his defensive work, failed to track back with any zeal, often leaving Santos to defend against more than one man.

Arsenal's New Problem

Flaws in an Arsenal team are nothing new, but after the most recent transfer window, Arsene Wenger had to confront an issue he has never faced while at the helm. For the first time in his tenure, Arsenal are a squad with no world class players.

Let's be clear. There are plenty of good ones. Some of them may even go on to become world class. But at this stage, would you even consider putting any Arsenal player in a composite XI of the world's best? Going back to Dennis Bergkamp, when Arsenal have had poor displays in the past, there was always a chance the likes of Thierry Henry, Robin Van Persie or Cesc Fabregas would produce a bit of inspiration to drag the team over the line.

This doesn't make Arsenal a bad team, and is a problem that can be easily overcome. But you have to ensure than the whole is greater than the sum of its parts. That was not the case against Schalke. When you have lots of "7 out of 10" players, but no "9's or 10's", it means that every member of the starting XI has to put their hand up. There can be no dead wood. Last night, Arsenal were a bunch of soporific logs.

When Saturday Comes

It's not the defeat, but the manner of it that is so alarming for Arsenal fans. You wonder if what is says about this Arsenal side is the maxim about how the measure of a team is how it recovers (or not) from a defeat. Personally I felt the handwringing over the loss to Norwich was premature. However, that may not be the case at 4:50pm on Saturday. Fail to win against QPR, and Arsenal have serious problems. Make no mistake, if they play like this at the weekend, they won't win.

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