The Royal Blues stumbled to a 2-0 defeat at Bayer Leverkusen on Saturday in the Bundesliga with Dutch coach Huub Stevens fuming he could have substituted nine players during a woeful display.
Midfielder Roman Neustädter says Schalke are now eager to put the Leverkusen defeat behind them and show what they can do against the Greeks with the Royal Blues top of Group B.
"We have checked off the game. We know that against Leverkusen everything went wrong that could go wrong," said the midfielder. "Now it's about going full throttle and focusing fully on Olympiakos.
"What happened to us against Leverkusen won't happen a second time."
Schalke have been guilty of erratic form this season, but showed their fighting spirit to come when they were 2-0 down to draw with Arsenal a fortnight ago at home by staying top of the group by a point from the Gunners.
Victory at the Veltins Arena would put Schalke in the knock-out phase, but it is likely to go to the final group match at Montpellier on December 4 to decide who wins the pool.
Stevens will be without Dutch winger Ibrahim Afellay, who is suffering from the thigh strain he picked up in Holland's win over Germany last week.
The Germans already have a win over Olympiakos under their belt after Dutch striker Klaas-Jan Huntelaar's winner in Greece, when the Oranje forward also missed a penalty.
Schalke captain Benedikt Höwedes had headed the Royal Blues ahead before the hosts equalised through Algeria midfielder Djamel Abdoun.
The Greeks come to Gelsenkirchen having kept alive their chances of reaching the knock-out phase after beating Montpellier for the second time in successive match-days.
Their 3-1 victory with late goals by Leandro Greco and Kostas Mitroglou in the last ten minutes sealed the win which keeps the Greeks third in the group and in with a fighting chance of reaching the next round.
They are just one point behind second-placed Arsenal FC and two adrift of Schalke.
But Schalke's US midfielder Jermaine Jones has said the Royal Blues are determined to finish the job and win the pool to give themselves a good chance of an easier draw in the knock-out phase.
"Basically, we are highly motivated for every game," he said.
"After the draw was made, everyone said that we would be the runners-up.
"We missed the chance to make it clear to Arsenal how things are, but we have the chance in our hands again and want to seize it with both hands."