Jerome Boateng's deflected late strike against his former side was enough for Bayern Munich to beat Man City 1-0.
Chelsea were held to a 1-1 draw by Schalke at Stamford Bridge in their opening Group G Champions League clash.
Aston Villa have announced manager Paul Lambert has signed a contract extension with the club until June 2018.
Man City goalkeeper Joe Hart admitted Jerome Boateng's late winner for Bayern Munich felt like a kick in the teeth.
Jose Mourinho bemoaned Chelsea's failure to kill off Schalke with a second goal before Klaas-Jan Huntelaar's equaliser.
Bayern Munich head coach Pep Guardiola felt his side deserved their 1-0 victory against Manchester City.