I just came across an article stating that Manchester City won the last 12 Premier League matches against Arsenal, but I know that things have changed over the years. Still that statistic is really telling. Was wondering whether Guardiola is still suspended, but seems he is not.
In the last season, Arsenal was a leader most of season but Manchester City began to take over a first position from Arsenal after their direct match. By losing against Lens in Champions League, Arsenal had a bad preparation for a match with Manchester City. They will play against Manchester City with not too good psychology after losing in Champions League and with pressure from recent head to head results against Manchester City, Arsenal will feel bigger pressure on their shoulders in an upcoming match.Quote
Guardiola is immensely complaining about Rodri missing the game and that the referee sent him off anyway. Can't recall the foul right now, but I am sure Manchester City has someone on the bench who is just good enough to play instead of Rodri. 
Guardiola should feel happy that he has many players to use and it is a big advantage than many other clubs and coaches in Premier League. Rodrid is important for Manchester City but as a big club, they have to go through it well and complaining won't help them to surpass this challenging time.