Olympiakos manager Zico explains his side must battle against exhaustion if they are to get anything out of their UEFA Champions League clash with Arsenal.
The Greek champions travel to the Emirates on Tuesday on the back of four games in the space of just 10 days.
Despite their recent good form the game against Arsenal will be the team's greatest test by far this season.
"We hope to play good football in London," Zico said.
"I am worried because of the tiredness. At the second half against Panionios (on Saturday) I saw tired players and this is something that I have to resolve.
"We hope to overcome the problem and have a good game. We know very well the difficulties of playing against Arsenal.
"They are a big club but we are confident of doing well in London. We must show that winning mentality that we show in Greece."
Meanwhile Olympiakos defender Olof Mellberg, who joined on a free from Juventus in the summer, stressed the need to stay focused at the back if the Greeks harbour any hope of getting anything out of game.
"We must stay focused and concentrated at the back because Arsenal under (Arsene) Wenger always play attacking football with good movements and good passing," he enthused.
"Their offensive line is really strong and I think that we will have a lot of work to do on Tuesday night.
"We are a good team also, with many experienced players and we will have our chance to make a good result there.
"It will be hard but we believe in ourselves and we will try to make our fans proud just like we did at the opener against AZ Alkmaar."