Even though José Mourinho was quick to play down suggestions that Chelsea are title contenders, their win at the Etihad proves otherwise. Chelsea combined astute tactics with great individual performances, and took advantage of the shortcomings of their opponent's squad and lack of plan B.
Manchester City started in their regular 4-4-2 formation even though they were hit with multiple injuries. Martin Demichelis was forced to play alongside Yaya Touré in central midfield in the absence of Fernandinho, despite Jack Rodwell being available for selection. Demichelis had a brief stint in central midfield against Tottenham last Wednesday, but that was against an already beaten Spurs side playing with ten men.
Chelsea started in a 4-2-3-1 formation, but the team selection was specific to their opponent. Ramires started as the right attacking midfielder, a selection that Mourinho tried out before away to Tottenham Hotspur, but had to abandon after 45 minutes. David Luiz started alongside Nemanja Matic in central midfield, forming a previously unseen, but robust partnership.
The holding midfielders
Both David Luiz and Nemanja Matic played as defensive holding midfielders, breaking up Manchester City's attacks. They were very narrow, and didn't drift much to the sides unless the narrow back four needed to become a bit wider, or if one of the full-backs had to push higher. The former happened if City were in possession on either side of the box, the latter if the Chelsea full-back had to push higher to apply pressure on the winger in possession, leaving space behind in the process.
This meant that City found it impossible to play through the middle, they had to involve the full-backs in the final third. This would have come naturally for City, but Zabaleta and Kolarov were reluctant to push high knowing that Chelsea had Hazard and Willian waiting to use the open spaces left behind by the full-backs.
Although Matic and Luiz prevented City from getting the ball in central areas in front of the box, their presence prevented Chelsea from passing the ball out from the back. The two of them stayed narrow even in possession, which made it easy for City to block them. Matic was particularly guilty of not occupying the far side in midfield during the build-up. Basically Chelsea were blocking themselves during their own build-up phase. This is the shortcoming of playing two blocking midfielders as holders. The team becomes "broken". The most famous example of such a midfield partnership is De Jong and Van Bommel in the Dutch national team during the 2010 World Cup. Just think of how one-dimensional the play of that team was even though it included attackers like Robben, Sneijder and van Persie.
However, Chelsea had a lot of success with goal-kicks. Ivanovic pushed very high, sometimes right onto Kolarov, winning three out of three aerial duels against the Serbian on the right wing.
Manchester City troubled Chelsea from low crosses for the most part. Matic or Luiz very rarely dropped between the centre-backs in the box, which made the back four of Chelsea vulnerable to crosses. Either Dzeko or Negredo moved between the full-back and the centre-back on the far side, which meant that the full-back had to come and play a bit narrower to help mark the striker. This freed up Navas to arrive at the far post and attack the crosses.
Demichelis in midfield
Manchester City have been exquisite in possession in previous games, but struggled against Chelsea. Playing Demichelis was an obvious drop compared to Fernandinho. The Argentine was marked closely by Willian, and sometimes Eto'o stepped back as well to crowd him out. This forced Demichelis to play the ball backwards or sideways instead of building the attacks.
Demichelis was an inadequate option in defence as well. He struggled to keep up with the pace of Chelsea on the counter-attacks, and often failed to spot and pick up runners from midfield. All in all this will not go down as one of his better games in a Manchester City shirt.
Hazard drifts to the center
Hazard was often coming inside from the left, which created an overload in central midfield for Chelsea. Luiz or Matic could stay behind, while Willian and Hazard played in the center, with the other holding midfielder becoming the third central player going forward, outnumbering Manchester City.
Ramires didn't hug the line either, but as a central midfield player one would expect him to drift to the middle. However his movement wasn't as dominant, as he was more disciplined in his marking of Kolarov. The Serbian full-back's overloads destroyed Manchester United earlier in the season, so it is fair to say that although Ramires wasnst as eye-catching as Willian or Hazard, his contribution was just as important.
Chelsea outnumber Manchester City in midfield: Touré marks Hazard, Demichelis does not apply enough pressure on Willian, who finds Matic in space.
Chelsea press successfully
Given that Chelsea's shape limited them in the build-up phase, it was crucial that they had to do as little of this as possible. Basically Chelsea had to win the ball as high up the pitch as they could, which at the same time limited the opportunities that City's best players -their world class attackers- had on the ball.
Willian had a key part in Chelsea's pressing. He stayed around Demichelis, limiting the time the Argentine could spend in possession. At the same time Matic and Luiz man-marked Touré and Silva. Chelsea's back four stayed back with the two strikers and Navas, who was playing so high that he became isolated and City failed to involve him in the build-up.
The movement of Ramires was key in Chelsea's pressing. He was forcing Nastasic to play the ball inside to Demichelis by running towards the left of Nastasic. This prevented the centre-back from passing to Kolarov, which also solved a problem that every side who intend to press has to deal with. The defenders are usually in numerical advantage against the attackers, which often makes the press ineffective, or teams tend to overcommit and get found out.
Given that Chelsea had limitations in the build-up it was surprising to see that Manchester City were not pressing as hard as they could have. The attackers were often applying only medium pressure, even at throw-ins, where the circumstances are ideal for winning the ball. Space is limited, the team in possession can reach only a fraction of the field with long balls, and you can get in front of goal in one or two passes.
When people talk about Chelsea as title contenders, they often mention the "Mourinho factor". This game demonstrated what people mean by that. Chelsea took advantage of Manchester City's shortcomings, but at the same time tried to make the most of their own advantages. You are not going to see the same starting eleven against a mid-table side at Stanford Bridge, but Mourinho adapted tactically to the opponent.
Manchester City were not playing as well as they could, however the injuries did not help. Aguero could have added pace and a different kind of movement to the attacks, but the injury of Fernandinho had a more important effect on how the game turned out. The game could have been very different had Demichelis played in defence. At the same time it probably didn't help that City were in a situation in which they rarely find themselves. They were outsmarted at home, and could not change once the initial gameplan proved to be ineffective.
José Mourinho had made it clear that he intends to get one point from their title rivals away from home, and wants to win the home games. The away win against Manchester City is a massive result, but there are still 42 points left to be played for. The title race is far from over.