Antonio Conte's 3-4-3 one of the 'key tactical trends' of the Premier League season

Chelsea "didn't discover the system," blasted Spurs manager Mauricio Pochettino at the journalists who questioned his use of a three-man backline against Arsenal last weekend.  He is right, of course.  Conte wasn't the first to use such a system, not even close, either in England or in Italy, but he certainly won't be the last either.  Conte has made three-man defenses fashionable again, with Spurs joining Everton, West Ham, and even the US Men's National Team as recent examples of teams who have (at least temporarily) shifted to such a setup — with varying degrees of success, it might be added.

This shift was highlighted in the Guardian's tactical review of the first quarter of the season, with Michael Cox, of Zonal Marking fame, naming it one of his "key tactical trends of the season so far".  The "system has been more visible than usual," writes Cox, pointing out that Manchester City have subtly shifted to a similar setup at times as well.

The three-man system isn't something one can pick up overnight however.  We've know this even a few years ago, when Mourinho's late-match changes, when behind, involved shifting to a back three and throwing on extra strikers.  While that resulted in at least one famous win (vs. PSG in the Champions League), Chelsea often looked disorganized and haphazard while playing in it.  Sort of like Everton last weekend, when they attempted to mirror Chelsea.  Their manager, Ronald Koeman spoke after the game about how impressed he was with Chelsea's implementation of the tactic.  And that, of course, is all down to the head coach.

"‘The first time I changed to this system was against Arsenal for the last 25 minutes, and then we continued with this idea of football. For sure in this month we have developed, we have worked a lot on this system, and for sure I have to say thanks to my players because they had the right concentration, the right attitude, the right will to stay more than before in the training sessions and now it is easier than one month ago. But we know we can improve a lot on different aspects - the pressure on the ball, quickly being more compact - for sure we have to improve."

Many expected Antonio Conte to use a three-man setup after his success in (and with) Italy over the past half-decade, but he reminded everyone right at the start that he used to use 4-2-4 with other teams and that he will definitely tailor his tactics to the squad he has available, rather than trying to shoehorn them into a preconceived hard-line notion.  And so we've seen the 442/424 combo and the 433/4141 combo, both emphasizing wide play with slightly different setups in the middle.  Chelsea were hardly solid in defense, but were scoring at a decent rate and so these tactics were, more or less, working.  Until the Liverpool and Arsenal games, especially the latter, that woefully exposed them, identifying structural weaknesses that could be exploited through single-points of failure (Cahill errors, Kanté getting turned, etc.).

In his big interview with the official Chelsea website this weekend, Conte explained how he arrived at the new formation and tactical system and how signings such as Marcos Alonso and David Luiz, who have been crucial to the success of the 3-4-3, were all part of a plan.

"We started the season with another system because the idea in my mind was that I wanted to play with the 4-2-4, and then we switched with 4-3-3 and we played also in the same way like last year, 4-2-3-1. But I noticed in some circumstances we didn't have the right balance because when you concede more goals than your opponent and even more chances to score a goal, it is never a good thing. For this reason, we switched to the new system of 3-4-3 and I think this is a good fit for our squad because also we have the strikers adapted for this system."

"I thought it would improve us offensively as well as defensively and we didn't lose our offensive situation. In this way we have increased it because we scored many goals and created a lot of chances to score the goals and also if you maintain the clean sheet, I think this is the right way."

[...]

"In the pre-season I preferred to work on the concept, on the principles and then you develop the system of play, but I always knew this squad could play with this 3-4-3 system. In my mind there was this possibility. I knew the characteristic of the players and for this reason when I spoke to the club and we planned the season, this system was an alternative to the 4-2-4."

-Antonio Conte; source: Chelsea FC

As Conte says, where Chelsea are now is the results of four months of hard work, of drilling not just tactics and fitness, but ideas, philosophies, and attitudes.  The three-man backline may be a tactical trend in the Premier League and beyond (alongside features such as counter-pressing), but the specific implementation of it remains wholly unique to this set of players, to this moment, with this coach.

"Conte's 3-4-3 is subtly different from the diamond midfield employed by Johan Cruyff and Louis van Gaal at Barcelona and Ajax, in which wingers stayed wide and defenders were essentially a springboard for attacks. It is different again from the deep-lying 3-4-3 (more accurately a 5-2-3 or even a 5-4-1) with which Martinez kept Wigan Athletic up in 2012."

"...Conte's 3-4-3 is a response to the strengths and weaknesses of the squad he has inherited: a shortage of defenders, quick and mobile attackers, and perhaps the Premier League's most energetic midfielder in N'Golo Kante."

-Jonathan Liew; source: Telegraph

Tailoring a certain formation to a certain situation, to utilize the unique strengths (free Hazard, for example) and mitigate the weaknesses (extra cover for defenders) — it's just as Conte promised on day one.  (Compare/contrast with the recent, or not so recent, op-eds around Mourinho's staunch refusal to change and develop, if you're up for opening that can of worms.)

"I like to say that the manager is like a tailor - that you must build the best dress for the team."

"Three at the back, four at the back... It's not important. What's important is the right spirit of the team and good organisation."

-Antonio Conte, July 2016; source: Mirror

Sure is a fashionable, trendsetting pretty dress we've got on Chelsea right now.