One of the main talking points in Enzo Maresca's first season as Chelsea head coach has been the positions and profiles of the players in his box midfield.
In possession, Chelsea have been playing in a 3-2-4-1 with Moises Caicedo as one part of the double pivot and Cole Palmer as either the right or left No 10.
The remaining two slots have been occupied by different players, with one of the full-backs, Malo Gusto or Marc Cucurella, roaming infield to partner Caicedo in the No 6 position or playing higher as a No 10 next to Palmer. Enzo Fernandez and Romeo Lavia have also featured in that box midfield, with the latter partnering Caicedo in the double pivot in recent matches against Manchester United, Newcastle United and Liverpool.
Maresca's preference for using his wingers as the widest players in this attacking shape -- because of their abilities in one-versus-one situations -- means that one full-back has to play a narrow role as a No 6 or a No 10 in possession. Questions have been raised about the suitability of Chelsea's current group of full-backs to operate as a No 10, but the strength of the Caicedo-Lavia partnership and Maresca's view of the wide roles leave few options to choose from.
"In this moment, Romeo and Moi (Caicedo) give us physicality, strength in the middle, and this is the reason we found the option (to play) Malo (Gusto) in the pocket," said the Chelsea head coach last Friday.
"Otherwise, when we play with Enzo, it has to be Enzo and then one between Moi and Romeo, and when Enzo moves (forward) we struggle a little bit in the middle in terms of physicality."
It's a balancing act, as Maresca explained, and the composition of the box midfield will depend on the identity of Chelsea's opponents, too. Yet, one thing that is interesting about their box midfield is how the No 6 moves forward to attack the space between the lines.
In the 1-1 away draw against Manchester United last Sunday, Chelsea continued with their 3-2-4-1 shape in possession with Gusto occupying the right No 10 position and Caicedo partnering Lavia behind him. Second-half changes switched things around, with Fernandez replacing Lavia and Cucurella moving infield ahead of him after the visitors flipped their system.
Maresca's side were less threatening in the second half at Old Trafford, but managed to equalise from a corner kick.
Here, in the build-up to that set piece, Fernandez is next to Caicedo in midfield...
...but as Chelsea's defenders circulate the ball, the Argentina international sprints forward into the space between the lines while Palmer drops to offer a passing option. Palmer's movement drags Manuel Ugarte towards the touchline, while Cucurella's narrow position (out of shot) stretches Casemiro.
Attacking the space between the lines by one-half of Chelsea's double pivot has been common this season. In the 1-0 away win against Bournemouth in September, Renato Veiga partnered Caicedo in midfield, and his movement into that area helped them score the game's only goal.
Veiga spots the gap between Bournemouth's right-back and centre-back, who is marking Christopher Nkunku. Veiga's run between Julian Araujo and Illya Zabarnyi attracts the Bournemouth centre-back...
... and moves him away from Nkunku. This allows Sancho to find the Chelsea forward...
... who then dribbles inside the penalty area and scores the winner.
In another example, against West Ham United the following week, Cucurella is in a deeper role next to Caicedo, as Palmer and Fernandez operate as the No 10s. Palmer's movement drags Guido Rodriguez deeper and with Lucas Paqueta focusing on Cucurella, there's space to attack in West Ham's midfield.
Before Colwill plays the ball to Fernandez, the midfielder spots Caicedo, who is in position to attack the space in West Ham's block.
Fernandez then finds Caicedo in the space between Rodriguez and Paqueta...
... before the Ecuador international puts Nicolas Jackson through on goal, and he curls the ball into the bottom corner.
The role of Chelsea's No 10s in this attacking move is vital because their positioning drags the opponent's midfielders and creates central space that one of the double pivots can attack.
In this example, from the 2-1 defeat against Liverpool last month, Gusto and Palmer are the advanced players in Chelsea's box midfield.
... Gusto drops to offer himself as a passing option. And the movement of Palmer and Gusto helps stretch Liverpool's midfield to create space in that zone. As Tosin plays the ball to Gusto, Caicedo moves forward...
Palmer and Gusto's positioning stretches Jones and Ryan Gravenberch, and with Lavia occupying the latter, Chelsea's full-back finds Caicedo between the lines.
The midfielder then finds Jackson's run behind the defence...
... and the centre-forward finishes the move by putting the ball into the back of the net.
It is moves like these that should help Chelsea lessen the creative burden on Palmer, and offer them different methods to create chances from central areas.
The profile of Chelsea's midfielders affects how the team attacks. Maresca should be given credit for introducing solutions to empower those options.