After looking relatively comfortable in the first term, Arsenal conceded twice in the second half, but they will still go through regardless.
Gonzalo Higuain and Jose Callejon scored for Napoli, while Mikel Arteta was sent off for the Gunners after receiving two yellow cards.
This is how the Arsenal players fared:
Arsenal Player Ratings
Szczesny: Composed and confident in goal. What more could you ask of a keeper?
Jenkinson: Made some forays down the right but occasionally left a bit of space behind him.
Mertesacker - Several last ditch clearances. Overall he was hard to get past.
Koscielny: Looked sharp in defence, nothing got by him.
Gibbs: The odd lapse in concentration, but nothing fatal.
Flamini: Mature performance from the Frenchman, pushing forward when needed and helping out in defence as well.
Arteta: Helped Arsenal to take control of midfield as the half wore on.
Rosicky: Worked well with Arteta and Cazorla to keep things ticking over in midfield.
Cazorla: Useful in Arsenal counter attacks, he was his usual fleet-footed self.
Ozil: Quiet evening so far from the German.
Giroud: Doing his best to get involved. Had one excellent chance that he couldn't convert.
Szczesny: Little he could do about the first goal. Possibly could have snuffed out the second. He was flawless otherwise.
Jenkinson: Had some trouble with Insigne and Armero in the second term.
Mertesacker: Felt the pressure a little as Napoli pushed. Largely held his own, though was too slow to shut down Higuain on the goal.
Koscielny: Not quite the perfection of the first half, could have done better on the second goal.
Gibbs: Sloppy on a couple of occasions, he survived largely unscathed.
Flamini: Let Callejon out of his sights in the lead up to the goal, but otherwise was solid.
Arteta: Certainly did his side no favours by collecting two yellow cards and getting sent off.
Rosicky: Played some nice passes in the attacking third, but nothing decisive.
Cazorla: Looked threatening whenever he had the ball at his feet, but could possibly have involved himself more.
Ozil: Very quiet. Noticed him even less in the second half.
Giroud: Was given even fewer opportunities after half time. Hardly his fault, but not very involved.