Manchester City 2 Chelsea 0: David Luiz proves no substitute for John Terry as Chelsea foundations crumble

Brazilian failed to replicate the defensive sturdiness that the Blues captain has provided this season

Chelsea manager Jose Mourinho looks mildly unimpressed with Jovetic's effort (GETTY IMAGES)

With one hasty wave of the arm, the key difference between Chelsea’s victory at the Etihad 13 days ago and their FA Cup struggles last night was grasped.

As David Silva and Samir Nasri wonderfully worked their way into the box after 68 minutes, it looked like the French attacker might have been a fraction offside. Rather than keeping focus on his man, however, David Luiz committed the cardinal error of looking to the linesman. In that split-second, the game was settled.

It is, of course, one of the most elementary instructions at every level of football. It was similarly the simple difference here.

Chelsea were less durable in defence, Manchester City were allowed to be more dynamic in attack. It was also the ironic twist to this tie.

Although Chelsea could afford to play their best team due to the fact they now have a week off – in stark contrast to a City side preparing for Barcelona – the League leaders endured a forced weakness in their strongest area.

John Terry remained out, Luiz again started, Gary Cahill hobbled back in beside him. Jose Mourinho had ‘confirmed’ on Friday – amid his series of barbs at Arsène Wenger – that Cahill would miss this game after suffering a calf injury in the midweek 1-1 draw at West Bromwich.

That possible attempted misdirection perhaps reflected an element of apprehension about his restructured defence. The root of Chelsea’s run to the top of the League has been their brilliant backline, and they have amassed by far the best defensive record in the division. Mourinho’s side have conceded just 21 times in 26 matches, which makes them the only team to have let in less than a goal a game.

It does not seem a coincidence that the only goal they saw go past Petr Cech in the previous five games, then, was at the Hawthorns in the period after Cahill took a knock.

That defence was similarly affected here, against a much better attack, and it told. This time, there was no keeping Manchester City at bay, or even barring their way to goal.

One of the most conspicuous qualities of Chelsea’s backline over the past few weeks has been their sure-footedness and ability to stand tall. That is the kind of resolve Cahill and Terry together give you.

It was particular notable in the League victory at this stadium just 13 days ago, especially after an initially chaotic opening period.

Here, it was almost the reverse. From about 10 minutes in, a reshaped City attack seemed to realise that they could pull the Chelsea defensive players about much more readily.

Although the considerable presence of Nemanja Matic was often placed right in centre and obstructing the route, Manuel Pellegrini’s forwards just started working around him.

This was City at least some of the way back to their best, after the frustrations of the past few games, and Chelsea a certain extent off it.

It is difficult not to pin a lot of this on Luiz, and the absence of Terry. For all the Brazilian’s obvious qualities, especially in central midfield, the defence just isn’t tied together quite as well. Chelsea’s greater waywardness reflected the occasional haphazardness that slips into his abrasive game. It was summed up in the 29th minute when he effectively challenged his own goalkeeper in air.

By then, though, Chelsea had already been rocked. There was ample warning in the 16th minute. Yaya Touré thundered through with a strike, Cech parried, Cahill was slow to react, and Luiz was caught somewhere in between. Fortunately for Chelsea at that point, Stevan Jovetic couldn’t strike the target.

The Montenegrin’s luck changed a minute later. In a lusciously slick attack, Jovetic was put through on the right, before slipping the ball past both Cesar Azpilicueta and Cech into the bottom corner.

Chelsea now had to build again, but from a less durable base. As a consequence, it always seemed they were on the edge of a precipice in the way they weren’t when Terry was in the team against the same opposition.

And so, after 68 minutes, came the moment that both summed up the issue and decided the game. Chelsea were simply waved away.