#1 Off the ball discipline - pressing
The secret to winning against City is off the ball discipline. The opposition has to accept that they shall see a lot less of the ball, they will have to soak pressure and they will have to defend with their lives.
Pep Guardiola's side play at a very high tempo and tire their opponents by wave after wave of attack. They can be relentless and at the first sign of lapse of concentration from the defending side, they pounce and kill the game.
As such, Chelsea will have to be very disciplined off the ball and it is not something that they have been good at recently. Only a team who matches City's tempo can dare to win the game.
Palace and Leicester City did it, and so did Newcastle. Even Chelsea, when they were full of confidence and vigour, got the better of the current Champions.
If Sarri can manage to keep his team disciplined without the ball and set his players up to press for the entire game, they will give themselves a very good chance of winning their first silverware of the season.