English football teams Chelsea and Arsenal were beaten in Champions League group play on Wednesday.
Jose Mourinho suffered a nightmare homecoming as Porto, the club he led to the Champions League title in 2004, inflicted a 2-1 defeat on his woefully out-of-sorts Chelsea side in Group G.
Mourinho sprang a surprise before the game by leaving out Eden Hazard, Nemanja Matic and Oscar and the Londoners went behind after 39 minutes when Yacine Brahimi produced a surging run down the left and Andre Andre scored.
Brazil playmaker Willian equalised with the last move of the first half, curling a delightful free kick into the top corner of the net from 25 metres.
Porto then went back in front seven minutes after the break when Maicon stooped low at the near post to head a left-wing corner past keeper Asmir Begovic.
Chelsea won the Premier League last season but are struggling sixth from bottom in their domestic championship this term.
Porto have four points from two games in Group G while Chelsea have three.
Arsenal's Champions League hopes were left dangling by a thread after they lost an astonishing clash 3-2 to Olympiakos Piraeus who won a competitive European match in England for the first time in 50 years.
After losing their opening game to Dinamo Zagreb two weeks ago, Arsenal are bottom of Group F, six points behind leaders Bayern Munich, who they have to play twice.
Olympiakos' 12 previous visits to England all ended in defeat.
Two late goals in two minutes from Sergi Roberto and Luis Suarez gave champions Barcelona a 2-1 home win over Bayer Leverkusen in Group E.
Bayern Munich striker Robert Lewandowski continued his remarkable scoring run with a hat-trick in a 5-0 thrashing of Dinamo Zagreb to snap the Croats' 45-game unbeaten run and put the German champions in control of their group.