Much has been made of Andre Villas-Boas' high line and its impact on a Chelsea defensive unit that suddenly finds itself in crisis. Five goals shipped to Arsenal at Stamford Bridge. Three conceded to Manchester United at Old Trafford. Only four clean sheets all year, in all competitions, out of seventeen matches. I mean, granted, Chelsea have only conceded more than one goal twice in those seventeen matches, but comparing the defensive record this year - 1.11 goals per game - to last season's 0.59 paints a worrying picture with about a quarter of the season gone.

No matter how you slice it, this isn't what we're used to seeing out of Chelsea (although comparisons to Jose Mourinho's 04/05 season are at best unfair and at worst disingenuous). The defence is hemorrhaging goals at the sort of rate we haven't seen since 00/01, and if that continues, it'll be trouble. We'll have a more in-depth analysis of the back line at some point in the near future, but for now there's an obvious issue to address. Here's Andre Villas-Boas to explain things to us:

You have to provoke them with the ball, which is something most teams can’t do. I cannot understand it. It’s an essential factor in the game. At this time of ultra-low defensive block teams, you will have to learn how to provoke them with the ball. It’s the ball they want, so you have to defy them using the ball as a carrot. Louis Van Gaal’s idea is one of continuous circulation, one side to the other, until the moment that, when you change direction, an space opens up inside and you go through it. So, he provokes the opponent with horizontal circulation of the ball, until the moment that the opponent will start to pressure out of despair. What I believe in is to challenge the rival by driving the ball into him.

You might recognise that quote: it's from a widely circulated interview that was republished in the Telegraph before the season started. Why do I bring it up here? Because Villas-Boas himself has highlighted the means by which an organised defence can be broken down - provoke them with the ball, drag them out of position when they press, and hit the space vacated. Does that sound familiar to anyone?

It should, because it's how Chelsea are acting at both ends of the pitch. In order to break down a team, the Blues look to draw the defenders out of position and then look to play someone - usually Ashley Cole or Daniel Sturridge - into the space that opens up behind the opposition. If they can't find that pass, they keep the ball. And, in turn, teams do the same to us.

The majority of the goals Chelsea have conceded fall under set pieces (a different kettle of fish, and one that I've covered earlier) or major individual errors leading to big chances. One suspects that our platonic goal conceded involves having a fullback sucked towards the ball and then someone played into the space that opens up, which is happening so much that it might as well be expected once a match, but many of the other issues Chelsea have had revolve around players matching up with the opposition and getting beaten, with no support from their teammates.

This isn't necessarily being caused by a high line or a particularly wide one but rather the pressing game Villas-Boas has implemented. Pressing is very much in favour at the moment amongst tacticians, and for good reason. Done correctly, it disrupts the opposition, preventing them from playing their game - we saw a superb example of this when Athletic Bilbao bludgeoned Barcelona into (relative) submission last weekend during the first half before rain made the game into something of a farce.

The concept of pressing is simple. You deny the opposition time to play and in doing so force mistakes that allow your team to repossess the ball. Pep Guardiola's Barcelona are the world's quintessential pressing team (which makes Athletic's display against them last week slightly ironic), and they've been hugely successful at keeping the ball in no small part due to their defensive strategy.

However, as with all things football, there's a tradeoff between schemes. The more you press, the easier it is for the opposition to do several things. The most obvious is to wear the defensive side out (this is why teams like Arsenal seem to turn their press on and off) but there are other issues too - mostly in terms of shape disruption and isolating individual defenders.

When you combine a heavy press with zonal marking, where each player is responsible for a specific area and is therefore free to be overloaded by multiple attackers coming at him, a heavy press from the back line can be suicidal. This is exactly what's happening to Chelsea whenever the ball comes towards the space between the centre backs and the fullbacks - players are being yanked out of position by chasing the ball and suddenly we're left with players isolated.

That wouldn't really be so bad if we could tackle, but this team has a problem there - out of the players who feature regularly, only Oriol Romeu John Terry and David Luiz are good tacklers for their position, and the latter's fouling habits make him an unsure bet as well. Essentially, the players on this squad are built to play in a highly organised defence, and once they're asked to go chasing, we have problems, leading to disciplinary issues and breakaways that are leaving Petr Cech ludicrously exposed.

The press is fine in and of itself, but it's a tool to use when appropriate, and right now it's being misapplied. That the problem hasn't been rectified despite Andre Villas-Boas being only too happy to exploit it in other teams is quite frankly baffling. Even Barcelona don't use the heavy press all the time - if they haven't recovered possession within six seconds they drop back into a typical defensive block and try again from there. Chelsea don't appear to do that, favouring something approaching suicide instead.

Ditching the high line and changing the personnel won't fix things. Having some semblance of defensive organisation might. Use the press, but use it intelligently. This all-or-nothing nonsense has to stop.