For the 2nd Premier League game running, Arsene Wenger chose to field a Denilson-Song-Fabregas midfield three but unlike the City game last weekend, Arsenal had to make do with playing against the 11 men of West Ham in a fixture that has been quite tight and low-scoring in recent years.
As such, this was the first true test of this new midfield's ability to break down a deep-lying defensive team. A similar system was in place against Partizan with Denilson the deepest midfielder and Song more box-to-box, but on that occasion Jack Wilshere played as the attacking midfielder in place of the injured Cesc Fabregas. Wilshere was of course suspended for this fixture and the one at Eastlands, had he been available it's likely we may not have seen this novel midfield system in place.
With Denilson holding the midfield and Fabregas supporting Chamakh in attack, Song was free to roam in between and contribute to both defence and attack. Much like Yaya Toure, Song is a player valued for his physical and defensive qualities but with the technical ability and intelligence to play higher up the pitch in a more direct and creative role. Potentially he's the best box-to-box player in the squad given his all-round abilities, intelligence and discipline (although Wilshere has also impressed so far this season), but the problem for Arsenal is that he's also by far the best holder. The question is which is better - Song holding/Denilson passing or Denilson holding/Song box-to-box? Wenger has opted for the latter in the last few games they've played together. Song brings added dynamism to the attack compared to Denilson, but at the same time still gets back to form a double defensive shield when the opposition have the ball in Arsenal's own half, so his re-deployment further forward may not necessarily weaken the defence.
Although each of the midfield trio had individual roles, there was considerable interchange with all 3 being comfortable playing deep or closer to the opposition box (Denilson less so). This seems to be a conscious decision by Arsene Wenger in an attempt to find new ways of breaking down the dreaded "parked bus" which has often been the scourge of this possession-based Arsenal side. With players moving out of their natural zones, they can lose their markers, draw players away from team-mates, and arrive un-noticed in dangerous areas. In particular, if the deepest midfielder - who often has no specific marker - is given the license to get into the opposition box, then that adds a whole new attacking dimension to this Arsenal side.
Of course this requires discipline and understanding between the midfielders in order not to leave the defence uncovered, this was painfully apparent against West Brom but on Saturday this didn't seem to be a problem.
As usual, some video evidence to summarise the key features of the new-look midfield: