F.C. Porto beat visiting Chelsea, 2-1, in the Champions League. It was a dismal return for Chelsea Manager José Mourinho, whose career took off when he coached Porto to the Champions League title in 2004. The result put Porto even with the Group G leader, Dynamo Kiev, at 4 points after Kiev won at Maccabi Tel-Aviv, 2-0. Chelsea has 3 points and Maccabi Tel-Aviv none. Chelsea lies 14th in the Premier League after a poor start.
A goalkeeping blunder by David Ospina helped Olympiakos beat host Arsenal, 3-2, and leave the Gunners in danger of their first Champions League group-stage exit in 16 years.