Olympiakos suffered their second consecutive defeat in Champions League Group F after losing 2-1 at Arsenal on Wednesday night in a game the Reds feel they should have drawn.
Arsenal manager Arsene Wenger rested some key players for the visit of Ernesto Valverde?s men, which handed a chance to teenager Alex Oxlade-Chamberlain, who opened the scoring in the eighth minute after poor defending from Olympiakos.
In fact, both sides produced lapses in defense in a very open first half. But it was the Greek side that paid the price for sloppy play in 20th minute when full back Andre Santos beat Olympiakos goalkeeper Franco Costanzo at his near post.
Raffik Djebbour missed a golden chance for the Reds before David Fuster gave the visitors hope in the 28th minute when he rose unchallenged to plant a header in the Arsenal goal.
The second half was a much tighter affair but Olympiakos almost grabbed an equalizer when captain Vassilis Torosidis curled a shot onto the bar.
It was a much improved performance from the Reds after their opening day defeat to Marseille at home but Valverde will be in no doubt of the tough task ahead as his side sits bottom of the group with no points. Arsenal has four points.
In the group?s other game, Marseille scored an emphatic 3-0 win over Borussia Dortmund. The French side has six points, the German champion, who Olympiakos faces next, has one point.