Arsenal lost for the second time in this season's Champions League after suffering a 3-2 defeat to Olympiacos.
The Greek champions took the lead through Felipe Pardo's deflected strike, before Theo Walcott levelled the scores.
An own goal from David Ospina saw the Gunners slip behind again, but Alexis Sanchez headed in to equalise after the break.
However, within a minute of drawing level, Alfred Finnbogason turned home Pardo's cross, to leave Arsenal in danger of facing an early exit from the competition.
Here, Sports Mole rates the performances of each player at the Emirates.
ARSENAL
Goal
David Ospina: Looked uncomfortable all evening and made a horrible mistake for Olympiacos's second goal, as he fumbled a corner into his own net. (3/10)
Defence
Hector Bellerin: Made a number of fine runs down the right for the Gunners all evening, with the Olympiacos defence unable to deal with his pace. (7/10)
Laurent Koscielny: Was not at fault for either of the goals his side conceded in the first half and eventually went off injured early in the second period. (5/10)
Gabriel Paulista: Shaky performance from the Brazilian, who struggled in the air. He also produced a number of rash challenges and was booked for a poor tackle. (4/10)
Kieran Gibbs: Did not make any mistakes at the back down his side of the pitch, but was unable to provide any support for his teammates going forward. (6/10)
Midfield
Francis Coquelin: Made a number of tackles and helped Arsenal dominate the midfield on his return to the squad, before he was replaced on the hour mark by Ramsey with his team needing a goal. (6/10)
Santi Cazorla: Saw plenty of the ball and always looked to create chances, but his final delivery failed to match his high standards this evening. (6/10)
Alex Oxlade-Chamberlain: Started the game brightly and fired a strike into the side-netting in the opening minutes, but faded as the night wore on. (6/10)
Attack
Mesut Ozil: Another underwhelming display from the German. He was involved in a lot of his side's attacks, but his final ball was poor on too many occasions. (5/10)
Alexis Sanchez: Good display from the Chilean, who was Arsenal's best player. He set up Walcott's goal with a fine through-ball, before scoring the second for the Gunners with a precise header. (7/10)
Theo Walcott: Kept up his impressive form in front of goal with a clinical strike in the first half. He also set up Sanchez's goal with an inch-perfect cross and his pace caused problems for the visitors all evening. (7/10)
Substitutes
Per Mertesacker: Came on for the injured Koscielny and almost found the net with a low strike that Roberto kept out. (6/10)
Aaron Ramsey: Replaced Coquelin in the centre of the pitch and was a positive influence on the match. Twice found Bellerin down the right with well-timed passes and always looked to get involved in the final third. (7/10)
Joel Campbell: Made no impact when he was brought on for Bellerin in the closing stages. (5/10)
OLYMPIACOS
Goal
Roberto: Although he will feel that he should have saved Walcott's effort, he produced an inspired display in the second half and made a number of vital stops as his team came under increasing pressure. (8/10)
Defence
Alberto Botia: Was caught out by Walcott as the England international raced in behind him to score Arsenal's first goal, but he was reliable for the rest of the evening. (6/10)
Omar Elabdellaoui: Made a vital clearance on the line to deny Cazorla's powerful strike and was solid at the back throughout. (6/10)
Dimitrios Siovas: Dominated in the air and showed his experience as Arsenal piled on the pressure in the second half. (7/10)
Leandro Salino: Struggled against Bellerin in the second half, but ended the match strongly. (6/10)
Midfield
Esteban Cambiasso: Fine display from the veteran Argentine, who made a number of vital interceptions and played a part in the winning goal. (8/10)
Pajtim Kasami: Committed showing from the former Fulham midfielder. He worked hard for his team all evening and was strong in the air. (7/10)
Felipe Pardo: Was heavily involved in all of Olympiacos's best moves. He scored their opener with a deflected strike, before his teasing cross was turned in by Finnbogason to seal the win. (8/10)
Kostas Fortounis: Proved a huge threat from set pieces as he found Pardo on the edge of the box to score the first goal and then saw his corner dropped over the line by Ospina for the second. (7/10)
Seba: Showed plenty of threat down the wing and always looked to help his team out at the back. (6/10)
Attack
Brown Ideye: Battled well against Koscielny and Gabriel in the first half, but was replaced by Finnbogason at the break. (6/10)
Substitutes
Alfred Finnbogason: Came on at half time and made a huge impact. His physical threat caused a number of problems for Arsenal and he grabbed the winner with a well-taken strike. (8/10)
Praxitelis Vouros: Brought on for the closing stages as Olympiacos came under heavy pressure. (6/10)
Hernani: Did not see too much of the ball when he came on to replace Seba late in the second half. (6/10)