Two ex-Atletico strikers – Fernando Torres and Sergio Aguero – were the most prominent players in a fast-paced, exciting clash.

Jose Mourinho played Gary Cahill rather than David Luiz, and left out Juan Mata with Andre Schurrle and Eden Hazard on the wings. Torres started after his two goals against Schalke in midweek.

Manuel Pellegrini used Martin Demichelis for the first time, played three central midfielders with Yaya Toure pushed to the top of the triangle, two ball-players on the flanks, and Aguero upfront alone.

Joe Hart’s huge error in the 90th minute decided the game, and overall this was evenly balanced.

Difference in style

On one hand, these two sides were playing utterly different styles. Mourinho wants his side to be efficient in possession, energetic down the flanks and devastating on the counter-attack, and the attacking trio fielded behind Torres represents his best pure counter-attacking format this season.

Pellegrini’s favoured style of play is based around ball retention, and here his starting selection offered more possession quality than ever before. This was the first time he’d used Javi Garcia, Fernandinho and Toure together in the same side, the first time he’d used Aguero upfront alone, and only the second time he’d used both Samir Nasri and David Silva on the flanks. This was a line-up selected to retain the ball in central positions.

The difference between the sides was particularly stark when you compared the passes received by the two sets of wide players:

City approach

The main talking point was Pellegrini’s overall starting selection – was he right to have omitted a proper number nine in preference for a holding midfielder? Daniel Storey at Football365 makes a decent argument that the approach played into the hands of a counter-attacking Chelsea side.

But the midfield selection was intended to prevent Chelsea counter-attacking through the middle. Even when City have been on fine form, and demolished Newcastle and Manchester United 4-0 and 4-1 respectively, the Fernandinho-Toure combination has looked prone to direct attacks through the centre of the pitch, as neither is a natural holding midfielder. City leave too much space between the lines with that midfield combination, and Oscar – Chelsea’s key player – surely would have had a field day had Pellegrini selected his usual 4-4-2ish shape.

There remain significant questions about Garcia’s ability, but simply by being another body in a deep central midfield position, he performed his role adequately in this contest. Oscar’s counter-attacking skill against a disjointed Schalke side in midweek was not replicated here, and he had little influence – aside from one clever turn midway through the first half to prompt a quick attack.

On this topic, the other question is about whether City’s possession-based approach pushed them too high up the pitch, leaving space in behind for the home side to break into.

The alternative would have been to sit much deeper, not insisting upon possession dominance and preventing Chelsea from constructing any counter-attacks – but the debutante centre-back partnership of Demichelis and Matija Nastasic would have been under huge pressure for long periods. It’s also not City’s natural approach. Playing higher up the pitch probably made sense overall, but there were clear problems with the defensive line in isolation.

City’s back four

Somewhat confusingly, City’s problems with balls played in behind seemed most obvious when they’d cleared the first ball at a set-piece, which would suggest the problem was with the positioning of the defence as a unit, rather than being indicative of a flawed overall approach from Pellegrini.

For example, Cahill’s early volley came from one of these situations, as did the incident when Torres attempted to chest the ball into the net from a Ramires cross. City’s back four were keen to take up a position on the edge of the box, but lacked a commanding centre-back – ie Vincent Kompany – to make the clearances when crosses were whipped in behind.

Chelsea’s opener came from Torres’ burst down the right, squaring for Schurrle’s tap-in. He had worked the channels very nicely all game, and although it was a slightly different type of attack to the manner Chelsea had previously been threatening from, it involved attacking the City defence directly, before the midfield could provide a shield.

Space behind the defences

The key to this game was attacking the space behind the defences. With Torres and Aguero roaming the channels and sprinting in behind, both sides needed to get the ball into the zone between opposition back four and goalkeeper.

Whereas Chelsea managed to do this because of City’s high defensive line, the away side had more problems. Overall, their midfield passing was actually very good – Silva orchestrated play wonderfully from between the lines, and Nasri’s impact was also impressive – doing something similar from the right.

But the long build-up play allowed Chelsea to defend deeper and deeper, until Cahill and John Terry were within their own penalty area. City had penetrative passes, and they also had runs in behind the defenders, but because Chelsea were defending so deep, City’s attackers found themselves receiving these through-balls at extremely narrow angles, unable to shoot. Silva twice collected passes almost on the byline, while Aguero had two efforts from very acute angles on the right.

For Aguero’s goal on 49 minutes, the difference was that City attacked directly through the centre of the pitch, giving Chelsea’s back four no time to adjust. They played three vertical passes – Garcia to Silva, Silva to Nasri, Nasri to Aguero. When the pass was played, Cahill and Terry were 30 yards away from goal, whereas when defending against City’s through-balls in the first half, they were often only 15 yards from goal. The finish was still hit from an amazing angle, but it was a much better chance.

Final quarter

The substitutes had relatively little impact on the shape of game, although arguably both managers made attacking changes in search of the winning goal. Perhaps the most surprising move, however, was Pellegrini’s decision to replace Nasri with Jesus Navas down the right, presumably an attempt to stretch the play.

But Nasri had been performing well, and was a key part of City’s gameplan – he also got the assist for Aguero’s goal. The shape City had at the end of the game – with Navas and Aleksandar Kolarov wide and Alvaro Negredo upfront alone – seemed more geared to a direct approach, which was a strange late shift in strategy.

Eventually, Hart and Nastastic’s mix-up resulted in Torres’ winner – a complete freak goal. But in the sense that involved Torres running past the defence from the channel, it summed up the game. Both sides were attacking the space in behind.

Conclusion

This was a game shaped by contrasting strategies but ultimately decided by a shocking individual error.

Chelsea rarely managed to counter-attack from their own half at great speed – that was partly because of Pellegrini strengthening his midfield zone, which also resulted in some very neat interplay in the final third.

But both sides thrived when they could attack in behind the opposition defence quickly. City’s back four seemed particularly troubled when asked to turn, while Chelsea’s back four knew their limitations and defended deep when they could – Aguero’s goal was a rare example of them being spun quickly.

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