Arsenal 2-1 Olympiakos
Oxlade-Chamberlain 8 Santos 20 Fuster 27
Early goals from summer signings Alex Oxlade-Chamberlain and Andre Santos proved enough to give Arsenal a narrow win over Olympiakos.
Oxlade-Chamberlain, 18, became the youngest English Champions League scorer when he waltzed across the area to plant a low shot into the corner.
Left-back Santos then cut inside to drive in a second before David Fuster headed in for the Greek side.
Mikel Arteta made a goal-line clearance as the Gunners held on for the win.
The visitors had the first sighting of goal but Fuster could only shoot wide after good work on the right-hand side from Ljubomir Fejsa.
But the home side were ahead in the eighth minute through 18-year-old Oxlade-Chamberlain.
Alex Song launched a long ball forward from the back and the winger took it down nicely on his chest. He cut across the penalty area from the right and after one of the three defenders in his wake failed to make a meaningful clearance, the Oxlade-Chamberlain was able to dispatch a low left-footed finish into the far corner.
Olympiakos had barely been in the Arsenal half but should have levelled in the 14th minute. A low corner was not dealt with and the ball fell to the feet of striker Rafik Djebbour, who saw his close-range effort brilliantly cleared from the goalline by Arteta.
Home defender Per Mertesacker had to be at his best to stop a dangerous cross from Vassilis Torossidis reaching Djebbour, but moments later Arsenal doubled their lead through Santos.
Tomas Rosicky released the left-back with a fine pass but his low cross was cut out by Ivan Marcano. However the Brazilian was able to collect the loose ball, cut inside and roll a right-footed effort past Franco Costanzo at his near post.
Marouane Chamakh then spurned a great chance to kill the game off when he ran onto Andrey Arshavin's lofted through ball but shanked his shot horribly across the face of goal.
And it was costly as Olympiakos pulled one back in
