Wojciech Szczesny - 8
Arsenal's most consistent performer this season has done it again, guarding his posts well showing agility and great reflexes to protect Arsenal's slender advantage.
Alex Song - 7
The stand in centre back for the game seemed to be playing in his usual defensive midfield position as Arsenal was holding a really high line. An rare assist to his name after a pin point cross for Chamberlain which resulted in the goal.
Per Mertesacker - 7
The giant defender read the game well and cleared any aerial danger with ease. Given time, he could put an end to Arsenal's defensive woes for good.
Andre Santos - 7
The new boys are going to give Arsene Wenger a selection headache for sure. Squared the ball for Chamakh who could not apply the finish, so he decided to finish it himself, beating Costanzo at his near post.
Bacary Sagna - 6
Not the best of days for the Frenchman as his defending was rather careless, exposing his keeper to unnecessary pressure.
Tomas Rosicky - 6
The entertaining and explosive Rosicky of before is no more. Behold the new boring, simple passing Rosicky.
Emmanuel Frimpong - 7
Full blooded tackles from the first to the ninetieth minute. Amazing to see him on the pitch for the full 90 minutes without collecting a card.
Mikel Arteta - 7.5
An enthusiastic Champions League performance from him. Managed to keep the ball out with his body to preserve Arsenal's slender lead in the first half, which proved to be a crucial block. His overall distribution and passing of the ball were also first class.
Andrei Arshavin (83' off) - 7
Finally, an improvement in Arshavin's game - running at defenders and taking shots.
Alex Oxlade-Chamberlain (66' off) - 8
Brilliant finish from the 18 year old, left footed bottom corner giving the keeper no chance. Another few more games under his belt and he might just kick Theo Walcott out of the starting XI.
Marouane Chamakh (70' off) - 5.5
Despite getting into good positions and chasing down the loose balls, the Moroccan's finishing were simply horrific. Needs to pull up his socks and learn to kill off games for the team.
Aaron Ramsey (66' on) - 6
Covered a lot of ground in the short time he was on and got into good goal-scoring positions but was unfortunate his team mate couldn't pick him out.
Robin Van Persie (70' on) - 6
An average performance from the new Arsenal skipper, who didn't want to overwork himself especially when there's an important game coming up on Sunday against Tottenham.
Kieran Gibbs (83' on)
Franco Costanzo - 5
Despite being a decade older than the young Pole at the other end of the pitch, his performance was woeful.
Ivan Marcano - 5
Could not cope with the pace of the Arsenal players and their swift passes often caught him off guard.
Olof Mellberg - 5
The man who scored the first ever goal in the Emirates Stadium didn't have a happy return to England and was unfortunate to concede a goal through his legs from Chamberlain's shot.
Jose Holebas - 5.5
The left back was tormented by the young Chamberlain, who just made his first appearance in the Champions League.
Vasilis Torosidis - 7
Had a crack on goal after Santos gave him too much space, rattling the crossbar in the process. Probably one of Olympiakos' best chance for an equalizer.
Pablo Orbaiz (75' off) - 5
Orbaiz was awful from the kick off and should have been taken off earlier.
Lubomir Fejsa - 6
Outclassed by the Arsenal midfielder, but was not to blame as he barely made a mistake and kept things simple in the middle of the park.
Kevin Mirallas (75' off) - 7.5
Gave the Arsenal back four problems with his energetic runs and shots from outside the box. The result could have been very different if he remained on the pitch for the last 15 minutes.
David Fuster - 7.5
The only man who attacked the ball from a corner was rewarded with a free header and a goal, while the red shirts were all rooted to the ground ball watching.
Rafik Djebbour - 7.5
Should have buried his golden opportunity to level the scores in the 14th minute, but the ball was cleared off the line by Arteta. Had another fierce shot saved by Szczesny. WIth the number of chances he had, his manager must be wondering how his team lost it.
Ariel Ibagaza - 7
The creative midfielder got his bearings right as all his passes found a team mate. One of the few Olympiacos players who took the game to Arsenal, especially in the second half.
Djamel Abdoun (75' on)
Francois Modesto (75' on)
Marco Pantelic (80' on)