Andre Villas-Boas was many things, but he was also, on occasion, entirely correct.

You can provoke the opponent with the ball, provoke him to move forward or sideways and open up a space. But many players can’t understand the game.

The key to opening up a well-organised defence is to draw them out of position. Intelligent movement of players and ball can provoke players to commit, push defenders around and generate space to attack. We've seen how the duo of Carl Jenkinson and Alex Oxlade-Chamberlain peeled open the Chelsea left wing for Arsenal's only goal of Saturday's match.

But what about the moment that nearly caused a hard-fought victory to fall apart? How did the defence let Olivier Giroud into a position where the Frenchman could have salvaged a draw by simply slotting into an open net?

It all started fairly innocently. Oxlade-Chamberlain has the ball in the Arsenal half, with Chelsea in a loose 4-4-1-1. It's slightly weird that John Obi Mikel's so high up the pitch, but as long as he can stop the youngster from blazing by him, perhaps turning him back to pass a defender, all should be well...

...oh. Oxlade-Chamberlain has skipped past Mikel as if he wasn't there, bursting into the space behind him and provoking Ramires into trying for a tackle. Note that both central midfielders, who are ostensibly supposed to be marking Santi Cazorla, have now engaged, and the wide midfielders aren't in a position to provide support. If Ramires' tackle fails, Chelsea have allowed Arsenal clean through their first bank of four defenders.

Which they have. Uh. Oh. Oxlade-Chamberlain has slipped the ball to Cazorla and started sprinting into the space that should have been occupied by Mikel and Ramires. Why was Cazorla free? Because he drifted between the lines, flank to flank, all game. There's no reason for Victor Moses to have picked him up -- his direct opponent is Kieran Gibbs -- and Branislav Ivanovic will not have wanted to over-commit and break up the second line of for. That leave Cazorla free to return the ball to Oxlade-Chamberlain.

Note that Gervinho's drifted infield to occupy Gary Cahill's attention; now he can pull him back out with a move to the flank. Olivier Giroud is running behind John Terry to get a little bit of space. Arsenal are the ones dictating Chelsea's shape at this point.

Although Eden Hazard's been in pursuit of him since the move began in the Arsenal half, Oxlade-Chamberlain's still going strong and is shown here racing onto the return pass by Cazorla. Cahill realises too late that Gervinho's going nowhere and Ivanovic isn't doing anything particularly useful. John Terry has to do something about it, and he chooses to try to get to the pass before Oxlade-Chamberlain. Cazorla's provoked Chelsea's final defender into drifting out of position.

Terry's too slow, and now Giroud has space to exploit. A simple ball through -- neither Ashley Cole nor Cahill can catch him -- and the French striker is one on one with Petr Cech.

Another game and this could have ended in tears. Fortunately it didn't, which means Chelsea can use this to learn some lessons. What can we take away from this chance?

Firstly, the way in which Arsenal manipulated our centre backs was worrying. They'd routinely use one of their wide forwards or Cazorla to form a two-striker shape, occupying a centre back, and then slowly drift wide to create a hole. This happened a number of times in the second half, and Chelsea never ever got wise to it. Here Cahill lets Gervinho pull him out of position, opening up the hole through which the final pass is played.

Secondly, and more seriously, this was a massive failure on the part of both pivot midfielders. That Mikel was so high up is worrisome -- a heavy press isn't required in injury time while holding a lead, and one of the downsides to pressing hard is that a technically able opponent can skip past you and take you out of play if you get too close. Oxlade-Chamberlain, who has the skill and speed to be a winger, can do that*.

*So can Ramires.

It's less of a surprise to see Ramires baited into a tackle he couldn't win. Ramires is a great player and a strong tackler, but he's very prone to chasing the ball at all costs rather than holding his position. The real estate in front of the centre backs was much more valuable to Chelsea than winning the ball off Oxlade-Chamberlain at this point in the match, so he should have held position as soon as he realised Mikel was caught too high up the pitch. I suspect that he would have fouled Oxlade-Chamberlain if he wasn't already carrying a yellow card; that would have also been an acceptable way of mopping the play.

This chance, then, could best be described as Arsenal provoking Chelsea's four most important defensive players to abandon their position in search of either the ball (Mikel, Ramires, Terry) or their man (Cahill). It's alarming that a move involving four players was able to cut so cleaning through the Blues' two lines, and it's more alarming still that the flaw was essentially one of discipline.

It didn't end up costing us, but if the centre keeps playing like this, it'll make for some rather unhappy times.