Arsene Wenger says Tuesday's Champions League visit of Olympiacos is a "must-win" game for his side's hopes of progressing from Group F.
Arsenal were beaten 2-1 by Dinamo Zagreb in their opening game of the competition earlier this month and welcome the Greek side to the Emirates Stadium in need of points ahead of a difficult clash with group favourites Bayern Munich in October.
Following a 5-2 success against Leicester City at the weekend, confidence is high among Wenger's squad, with Francis Coquelin in line for a return from his knee injury.
Mathieu Flamini and Mikel Arteta are doubts however, as Wenger prepares for a crucial clash in north London.
"It is already a must-win. You sum it up well," he told reporters.
"We have to win at home to qualify, as simple as that. we cannot afford to drop points at home now.
"Both teams will always try to go forward. At home, teams try to regroup and you have to be clinical.
"Coquelin has been back in training since yesterday. He looks alright. Flamini and Arteta have slight muscular problems."
Alexis Sanchez got off the mark for the season with a hat-trick at the King Power Stadium on Saturday, with Theo Walcott also on target.
The pair will likely be tasked with helping cover the void left by suspended striker Olivier Giroud - the Frenchman sent off in Zagreb.
Alex Oxlade-Chamberlain - who made his Champions League debut against the Greek side in December 2012 - added: "Alexis got off the mark and Theo was brilliant.
"Sanchez is one of the most passionate players I know. I look and learn from him."
