Goals from Jack Wilshere in the first and 65th minutes at the Emirates Stadium sealed Arsenal's convincing win, in which Mesut Ozil had a first-half penalty saved.
Arsenal had 13 attempts on goal and should have scored more, but they still won easily, posting their fourth Group F win from five attempts.
A point in Napoli in their last pool match will guarantee Arsenal of qualification to the round of 16 - they can also go through if they lose and Marseille beat Borussia Dortmund - and Wenger feels this is well within the reach of his team.
"We were in control and it looked sometimes, yes, that we lacked a bit sharpness to finish the game off," the Frenchman told ITV.
"Overall we were always in control and our only regret is that we could have scored more goals.
"You have 12 points and five games. That's a good number of points. I'm confident we can take a point or three in Naples to go through.
"It's an interesting one of course, a difficult one. We have played other difficult games away from home against other opponents and did well. That's what we have to put in our mind."
When asked about Wilshere's performance, Wenger added: "He showed me he can score goals.
"The most important thing in a good football team is that you have many players who can score and many players get chances."
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