Arsenal star Olivier Giroud scored his second of the night just minutes after the half-time break to stun Olympiakos and hand the Gunners a two-goal cushion.
The visitors know that a 2-0 win would be enough to see them leapfrog their Greek rivals in Group F into second place and secure their spot in the knockout stages of the tournament.
Having taking the lead in the first half after great build-up play from Mesut Ozil and Aaron Ramsey had set up Giroud to score his first of the night, it was Joel Campbell who produced a piece of individual brilliance to set up his teammate for the second.
The Costa Rican international showed great control and skill to bring the ball down and jinx his way past the Olympiakos defenders before sliding in a perfectly weighted ball for Giroud to slot home.
With the likes of Alexis Sanchez and Santi Cazorla ruled out through injury, Wenger needed his squad to step up and they have undoubtedly responded so far.
With this result or better, the Gunners will join Bayern Munich in the next stage of the Champions League, although they remain in a precarious position as a goal for the hosts would put them back in the driving seat.
Arsenal must win 2-0 at least or by a scoreline of 3-2 or better in order to advance through the head-to-head record, and after a slow start to the encounter, the visitors grew into the game and silenced the home crowd as the tension continues to increase at the Karaiskakis Stadium.