German international Ozil, signed from Real Madrid, dispatched a classy finish after eight minutes following a fine cross by in-form Wales midfielder Aaron Ramsey.
Ozil then turned provider to set up Olivier Giroud for a quick-fire second with just quarter of an hour played to leave Rafael Benitez's men shell-shocked.
It was a 10th straight win in all competitions for Arsene Wenger's side, who have stormed to the top of the Barclays Premier League and now look on course for safe passage through to the knock-out stages of Europe's elite club competition.
Arsenal's victory was, however, somewhat overshadowed by reports of trouble caused by Napoli fans as they vandalised shops on Holloway Road en route to the stadium.
It was a bright opening by Arsenal, who started with England midfielder Jack Wilshere on the bench as Mikel Arteta came into the team along with fit-again Czech playmaker Tomas Rosicky, while teenager Serge Gnarby, who scored in the win at Swansea on Saturday, was among the substitutes.
The Gunners swept into the lead with a goal of the highest quality.
Giroud, who turned 27 on Tuesday, laid the ball out to the right as Ramsey darted clear.
The Wales midfielder, enjoying a fine personal start to the new campaign, strode towards the by-line before looking up and clipping a perfectly-weighted pass back towards the penalty spot. Ozil arrived on queue to cushion an instinctive half-volley past former Liverpool stopper Pepe Reina to open his Arsenal account in some style.
Before Napoli - missing injured Argentina striker Gonzalo Higuain, who was one of Wenger's summer targets - could mount a recovery, they trailed 2-0 after 15 minutes.
Source: PA
Source: PA