With the absence of Theo Walcott, Tomas Rosicky came into the first XI on Saturday. Rosicky is a different player to Walcott, and looks to come inside more than Walcott.
At times, it looked like Arsenal were playing a Spanish like 4-2-3-1/4-2-2-2, with Rosicky joining Fabregas.
Let’s look at the 3rd Arsenal goal
Here, Rosicky and Denilson (black underlined) are the 2 deepest midfielders, while Fabregas and Song (in red) are the two furthest. Arshavin is out of picture, and Chamakh is in green.
With Rosicky tucking in, there’s noone on the right wing, and Arshavin is on the left, but drifting in. This is similar to Spain’s system early in the World Cup; Villa nominally on the left but cutting in, Torres up front, Iniesta nominally on the right cutting in to the middle with Xavi and Sergio and Alonso holding. It’s a similar system here (though Song is not an attacking midfielder)
Here, Arshavin has joined the attack, giving Arsenal 2 defined front players and 2 defined attacking midfielders. To me, the formation seems a 4-2-2-2. While that formation can create natural width by players finding space, and some wonderful football (it was used by Brazil in 1982), the lack of a direct outlet on the right could hinder Arsenal, which is why it’s important the fullbacks can deliver good crosses when they do get forward, or Arsenal have a direct outlet like Walcott available.