Pep Guardiola reveals why captain Vincent Kompany was substituted off in their EFL Cup defeat to rivals Manchester United.
It's been said many times that Arsenal's depth this season is stronger than in recent years, and these midweek games showed why that's important.
Mata, 28, scored the only goal of the game as United beat Manchester City 1-0 in the EFL Cup fourth round at Old Trafford on Wednesday.
The Football Association has launched an investigation into the violence, with the Metropolitan Police having confirmed that seven arrests were made.
Stewards and police in riot gear were forced to come between supporters squaring off in the Sir Trevor Brooking Stand of the London Stadium.
Pep Guardiola has said he substituted Vincent Kompany at half-time in the 1-0 EFL Cup defeat to Manchester United because he told him he was tired.