Arsenal face must-win tie against Olympiakos says Wenger

Wenger's team slumped to a sloppy 2-1 defeat in their opening Group F fixture at Dinamo Zagreb and with a double-header next against Bayern Munich, the Arsenal manager knows there is now little margin for further error.

"You have to win your home games if you want to qualify from the group stage, it is simple as that," Wenger said on Monday.

"We cannot afford to drop points now against anyone at home."

Greek league leaders Olympiakos have won all five of their domestic fixtures this season, although they have a terrible record playing away to English clubs in Europe.

"They are a team with a big advantage - they dominate their league easily, so they can prepare for these kinds of games," Wenger added.

"They are well organised and have some players who know the Premier League, like (Esteban) Cambiasso and (Pajtim) Kasami who both played in England."

It has been a poor start for English sides in Europe's elite club competition this season, with defeats for both Manchester clubs as well as Arsenal.

Wenger, though, does not believe any conclusions can yet be drawn about the chances of a Premier League team winning the tournament.

"The Premier League is very, very tough. Is that an influence or not? I don't know, but it's a bit early to come to any conclusions. We have to wait a little bit longer," he said.

"A second year without us being successful and you could come to a conclusion of, 'yes, there is something we have to analyse deeply', but I don't believe so at the moment.

"Are we far away? I don't think so, but we have to show that with our performance."