West Ham boss David Moyes expects a battle tomorrow night against Europa League opponents Olympiakos.
The Hammers host the Greeks a fortnight after their defeat in Athens.
Moyes said, "They're a very experienced European team who have played a lot in the UK.
"I watched them play against Arsenal a couple of years ago. We're up against a good team.
"Our group is probably the toughest group we've had in three years so we'll have to play well.
"There were difficult challenges in Olympiakos.
"Out there, their crowd was phenomenal and they played a huge part on the day. Also, on the day, we didn't play well - no where near our standards - so we want closer to our usual best tomorrow night.
"If we win tomorrow night we're in a good place and we want to get the wins to qualify and be in Europe after Christmas."
He added, "There are some brilliant stadiums in the UK when they're rocking, but I think we all enjoyed the atmosphere in Olympiakos.
"We have a lot of good things going on in the Premier League but I genuinely think, if you go and watch games in Europe, the atmospheres can hit other levels."
