Valiant Olympiacos held Bayern Munich for 68 minutes before the usual suspect Robert Lewandowski scored for the German giants who reached the Champions League knockout stages with a 2-0 victory on Wednesday.
Ivan Perisic scored the second a few minutes before the final whistle.
Bayern were kept at bay due to Olympiacos defensive display and the brilliance of goalkeeper Sa who made several fantastic saves.
Olympiacos, who have just one point after four games lie at the bottom of the group.
The Greek Super League leaders must collect as many points as possible from their final two matches in order to have a hope of clinching third place which would mean a spot in the Europa League.