Alonso's Right-Back Midfield Experiment Cannot Hide the Fatal Flaw of the Back Three System

Among the many discussions surrounding Chelsea and Xabi Alonso, one obstacle has been overlooked: overcoming it would require a complete rewrite of the Premier League's tactical manual. Alonso wants to compete for honours with a formation regarded as clumsy and unconventional — the feared back three.

The fatal flaw of the back three: the two-man midfield

If you want to know how English football views the 3-4-3, ask about the 'ghost' of Ruben Amorim. It still haunts the Premier League, and its shadow is far greater than the back-three system Antonio Conte used to lead Chelsea to the title in the 2016/17 season.

Alonso would certainly be aware of this. Therefore, his unconventional setup on Sunday — using a right-back in the central midfield position — should be viewed as a classic distraction: shifting attention toward personnel choices while avoiding scrutiny of the system that once 'killed' Amorim.

The fatal weakness of the 3-4-3 lies in its two-man midfield. In theory, two attacking midfielders ahead can create a box structure and produce a four-versus-three advantage in the opponent's midfield area; alternatively, one centre-back can step forward to join the midfield. But the reality Arsenal showed on Sunday was often completely different.

Mikel Arteta dismantled this setup from two directions. Riccardo Calafiori moved inside from the left-back position into central areas, while Kai Havertz dropped back from the attacking line, giving Arsenal an overwhelming five-versus-two numerical advantage in midfield. This advantage repeatedly cut through Chelsea's defensive structure and eventually led directly to the winning goal.