London - Arsenal must win all three home games in Group F of the Champions League, starting with Tuesday's match against Olympiakos, manager Arsene Wenger said on Monday.
A surprise 2-1 defeat away to Dinamo Zagreb in their opening match has left Arsenal with little margin for error as they host the Greek side and the task is further complicated by a looming clash with Manchester United on Sunday.
Wenger made six changes for the Zagreb game, which took place only three days before an important Premier League match away to champions and London rivals Chelsea.
However, Wenger said his selection will not be influenced by next weekend's home clash with the Premier League leaders.
"The weekend game will not interfere," he told a news conference. "I don't believe it's down to selection at all. The 20 fit players I have available can play in every single game and I'm confident we have a very strong team.
"Basically the same team played at Tottenham and won in the League Cup in a much more difficult game physically. It was just that on the night (against Zagreb) we didn't play well.
"You have to win your home games if you want to qualify. It's as simple as that. We can't afford to drop points against anybody at home."
Striker Olivier Giroud was sent off in Zagreb and is suspended, while experienced midfielders Mathieu Flamini and Mikel Arteta are out injured.
The Greeks, who lost their opening group game 3-0 at home to Bayern Munich, have met Arsenal in three previous campaigns, winning all three home meetings but losing each time in London.
Under Wenger, Arsenal have reached the second stage of the competition every season since 1999-2000, but for the past five years in they have gone out in the first knockout round.
Last season was a particular disappointment with an away goals defeat by unfancied AS Monaco after losing 3-1 at home.