The Greek club take on the Gunners at the Emirates Stadium in their second Group B Champions League fixture and the Spanish midfielder is confident of making life difficult for the home team.
"Many times Olympiakos have tried to defeat Arsenal. This could be the moment to cause a surprise.
"We need to take something at the Emirates. No points from two matches (following our loss to Schalke) would make things difficult for us."
Fuster added: "Arsenal's defeat to Chelsea (in the Premier League on Saturday) could work for us or against us. They will want to respond, but they now have added pressure to please the fans. It is a tricky situation.
"Our ambition this season is to progress in the Champions League and we have always believed that is possible from day one."