I really don't know why City is performing below their standard. They have one of the best squad in the premier league and also the best manager so far.
So how come they are performing poor?
One of the things I have observed about city is their defensive loop holes. They focus more on attacking than defending. Which doesn't bring a balance to the team.
The simple reason to explain that is low work rate especially for their forwards. It's okay they stay upfront, but all of their forwards played like worst version of sterling. They're so damn lazy in tracking the ball back when they missed it. They also lack of workrate to help in defending against the opponent. All the time they did after failed to attack were jogging.
So it's not right by blaming their defense as their attackers have to be more sensitive with their work off the ball.
If you were watching the game. You should aware how it's very hard for all of City forwards to fall back. If they could have better work rate, i believe they would be winning it.