The deafening jeers that greeted former Barcelona boss Pep Guardiola before kick-off turned into away-fan cheers thanks to Manchester City's fine victory.
Noni Madueke scores twice and Gabriel Martinelli scores a third for Arsenal to beat Club Brugge 3-0 and maintain their Champions League winning streak.
Goals from Nico O'Reilly and Erling Haaland give Manchester City a 2-1 victory over Real Madrid at the Bernabeu, to pile pressure on Madrid manager Xabi Alonso.