Arsenal’s Champions League campaign is in serious peril after they went down 3-2 at home to Olympiacos for a second embarrassing defeat in as many games in this season’s competition.
Alexis Sanchez and Theo Walcott had twice levelled for the Gunners after David Ospina’s blunder had gifted the Greeks an early lead, but Alfred Finnbogason scored the winner at the Emirates Stadium.
SEE MORE: Arsenal player ratings from 3-2 defeat: Gunners sink to Olympiakos after Ospina gaffe
Finnbogason’s strike came within a minute of Sanchez’s equaliser, and leaves Arsenal, who lost to Dinamo Zagreb on matchday one, without a point ahead of back-to-back games against Bayern Munich.
Pep Guardiola’s side had no such problems dispatching of Zagreb. Robert Lewandowski bagged a hat-trick, taking his tally to 10 goals in three games, in a 5-0 rout which keeps them top of Group F.
Chelsea are not in anywhere near as much trouble as their London rivals, but a 2-1 loss to Porto was a fifth defeat of the season for the Blues – as many as they suffered throughout the whole of last term.
Andre Andre gave Porto the lead before Willian earned Chelsea half-time parity with a wonderful free-kick past ex-Real Madrid keeper Iker Casillas – making a record 152nd appearance in the competition.
But more poor defending from Jose Mourinho’s side gifted his former club a set-piece winner through Maicon, and Chelsea are now third in Group G after Dinamo Kiev’s 2-0 win at Maccabi Tel Aviv.
Defending champions Barcelona survived a scare at the Camp Nou against Bayer Leverkusen, who held the lead for nearly an hour after a 22nd-minute opener from defender Kyriakos Papadopoulos.
Without the injured Lionel Messi to save them, youngster Sergi Roberto stepped up to equalise on 80 minutes, before Luis Suarez got the Spanish giants over the line with this goal 90 seconds later.
There was a shock in Group E’s other game as BATE Borisov raced into a 3-0 lead against Roma and held on for a famous win despite second-half goals from Gervinho and Vasilis Torosidis for the Italians.
Elsewhere, in Group H, Zenit St Petersburg made it two wins from two with a 2-1 success over KAA Gent, while Valencia got their first victory back in the Champions League by beating Lyon 1-0 in France.
Bayern player ratings with video from 5-0 win over Zagreb: 10/10 striker poised to destroy Arsenal
Porto 2-1 Chelsea player ratings: Defence flops as Jose Mourinho loses to former club
Theo Walcott Olympiakos goal video: Watch Arsenal star extend impressive form with CL goal