Olympiacos coach Panagiotis Lemonis has warned his side that any mistakes will be punished by a lethal Chelsea attack when they meet in their Champions League clash in Athens.
Olympiacos face the Blues in the first leg of their last-16 tie after they reached the knockout stages from a group that included Real Madrid, Werder Bremen and Lazio.
Lemonis, who gained his coaching expertise in England, accepted that the Premier League side are favourites to reach the quarter-finals but his Olympiacos side will not roll over easily.
'Chelsea are not the most spectacular team in Europe, if the truth be told, but they are strong in every aspect and very tough to beat,' Lemonis said.
'They are very compact, excellent in defence, and lethal in attack. In games like these, you have to keep errors to a minimum.
'Our chances will depend on how we play defensively, just like in our previous matches in the competition. Chelsea are favourites, of course, but we are determined to put up a fight.
'The only thing that bothers me is when I see my players lacking passion, strength or determination on the pitch.
'My only demand for the games against Chelsea is to be proud of our performances afterwards. We are waiting impatiently to see how the coming weeks unfold.'
Among the Olympiacos squad is former Portsmouth striker Lomana LuaLua who credits current Chelsea coach Avram Grant with helping to put his career back on track.
LuaLua left England after the death of his 18-month-old son Jesus, who died of pneumonia while he was away on international duty at the 2006 African Nations Cup.
He was also arrested after an incident with a former partner but despite all the heartache which followed, LuaLua kept faith in the game thanks to some calming words from Grant.
Grant was director of football at Pompey when LuaLua was going through a tough period and revealed he was also a true friend at a time when he was thinking about quitting the game for good.
'Avram is a top man and was a good friend to me,' said LuaLua.
'I was having a bad time coming to terms with the death of my baby son and had fallen out of love with football. It did go through my mind to retire.
'I spoke with Avram a lot and he told me to keep smiling and things would work out for me.'
Olympiacos will face a Chelsea side that has to find a way to accommodate Michael Ballack and Frank Lampard in the same midfield as well as Nicolas Anelka and Didier Drogba in attack.
Grant has a fully fit squad to choose from although Andriy Shevchenko has not travelled with the squad as he is not deemed to be fully match fit.
Chelsea arrived in Greece after a six-hour flight from Gatwick on Sunday - circling a snowbound Athens airport for two hours before finally being allowed to land.
It was only the fourth fall of snow in the Greek capital in 26 years and many flights were cancelled but Chelsea were allowed to touch down after the runway had been cleared of snow and ice.
Many of Chelsea's 1,700-strong travelling fans found their flights cancelled or delayed on Monday and some of those who did make it into the air found themselves diverted to various Mediterranean islands.