It was a relatively sedate 0-0 at the half-time interval when Manchester City manager Pep Guardiola changed the course of the game with two bold substitutions.
Gunners are back up to third in the Champions League table
Manchester City held out for 2-1 win to knock out the home side Manchester United and set up semi-final against Arsenal
The Australian manager said the fixture list was ‘not manageable’ if teams do well in multiple competitions