Arsenal manager Arsene Wenger warned his side are already facing a must-win game in only their second Champions League group tie against Olympiacos at the Emirates Stadium.
The Gunners host the Greek leaders, who have won all of their five domestic fixtures, needing to recover from a disappointing opening Group F defeat away to Dinamo Zagreb, where striker Olivier Giroud was sent off.
With a double-header next against Bayern Munich, Wenger said: “You have to win your home games if you want to qualify from the group stage, it’s as simple as that. We cannot afford to drop points now against anyone at home. Olympiacos dominate their league, they are a team with a big advantage - they dominate their league easily, so they can prepare for these kinds of games.
“They are well organised and have some players who know the Premier League, like (Esteban) Cambiasso and (Pajtim) Kasami, who both played in England.”