Wellington Phoenix showed the way, and Sydney FC duly followed, putting five goals past a hapless Melbourne Victory side on Australia Day. For the second week in a row, Melbourne looked lost playing against a side with a 4-4-2 diamond formation, and Sydney FC exploited the gaping weaknesses left by their opponent.

Last week, we looked at Melbourne Heart’s use of the ‘diamond’ formation. While Heart’s version of it is unique, the formation is having somewhat of a renaissance in the A-League, with both Wellington Phoenix and Sydney FC using it as their current system of choice.

The strengths of the ‘diamond’ system perfectly exploit the weaknesses of Victory’s “Jekyll and Hyde” 4-2-2-2 system. Earlier in the season, Richard Parkin highlighted the two fundamental challenges for Victory’s system - “Firstly, how to dominate the midfield battle; and secondly, how to neutralise attacking full-backs”. Sydney FC, playing with a 4-4-2 diamond, thrived in those areas where Melbourne are weakest.

Melbourne Victory’s system leaves them outnumbered in midfield (1) and leaves space for the opposition fullbacks to attack (2) Photograph: Graphic

Sydney had a 4 v 2 scenario in the middle of the park (1), and in knowing the Victory’s wingers “cheated” defensively (ie don’t track back defensively, to stay forward for a potential counter attack), the full-backs had spaces to attack (2).

Sydney FC’s midfielders had ample time on the ball to pick out teammates and were near flawless with their execution. Hagi Gligor (100% passes completed), Terry McFlynn (100%), Milos Dimitrijevic (94%) and later Nick Carle (88%) had time and space to keep possession comfortably and also to pick out incisive passes further forward. Alessandro Del Piero was able to attempt 57 passes, more than double his season average of 26 (although he had been substituted early in previous matches), such was the time and space afforded to Sydney in the middle of the park.

The second and third goals highlighted the strengths in Sydney’s system and also the weaknesses in Victory’s.

Second Goal (Del Piero penalty)

The build-up which leads to the second goal for Sydney FC, a penalty which was converted by Del Piero Photograph: Graphic

When Sydney had the ball in midfield, as previously mentioned, they effectively had a 4 v 2 situation. Even when McFlynn, the deepest midfielder, dropped between the centre-backs to help Sydney play out, they still had a numerical advantage in midfield.

In the build-up to the second goal, when Dimitrijevic received a pass from Gligor, he was able to draw three players and maintained possession neatly. But both of Victory’s midfielders – Leigh Broxham and Rashid Mahazi were drawn forward, leaving space in between the lines for Del Piero.

Del Piero was able to receive in space from Nikola Petkovic before being pressured by Mahazi. Because of the sheer lack of numbers in midfield for Melbourne, Del Piero was able to combine with Dimitrijevic, who became free when Mahazi pressured Del Piero.

Mahazi was left to chase shadows, as Dimitrijevic and Del Piero exchanged passes, before the Italian picked out striker Ranko Despotovic, who was fouled by Adrian Leijer. It was a perfect example of how Sydney’s midfield diamond was able to comfortably win the midfield battle.

Third Goal (Sebastian Ryall, aka Franco Baresi)

Sydney’s third goal, with a forward run by Sebastian Ryall causing havoc Photograph: Graphic

The third goal also started as a result of the midfield battle, but the goal came from a swashbuckling run from Sebastian Ryall, Sydney’s right-back.

McFlynn was able to win the ball back in midfield, after Sydney pounced on the isolated duo of Broxham and Mahazi. The ball then found its way out to Ryall who burst forward untracked.

Normally, in a situation where the opposition full-back was on the ball going forward, Melbourne’s central midfield will slide across to help the fullback create a 2 v 1 situation (as represented by the red arrow). But in this case Broxham failed to do so, either because he wanted to avoid being drawn out wide, which would have further accentuated the space in midfield for Sydney, or because he was simply too exhausted after chasing shadows for 25 minutes.

Ryall was then able to cut inside, exploiting the gap between rookie left-back Dylan Murnane and Broxham and then embarrassed the Victory defence (credit must also go to McFlynn for his decoy run which momentarily drew the attentions of Nick Ansell).

It was a superb all-round tactical display from Sydney FC and manager Frank Farina. Everything was thought of and executed, right down to the positioning of the two strikers in defence, forcing Melbourne to play through midfield where they were hopelessly undermanned. The ‘diamond’ formation exploited Melbourne’s two gaping weaknesses: with extra numbers in midfield and space for the full-backs to get forward.

Despite all the gloom and doom, incredibly, Frank Farina has now overseen Sydney FC’s longest winning streak (four), their biggest ever victory (7-1 against Wellington Phoenix) and now the biggest ever away win against Sydney’s greatest rivals. The problem for Sydney FC is, and has been, inconsistency, something Melbourne Victory know of all too well.