The Gunners allowed a two-goal lead in a meeting with Schalke on Tuesday to slip through their grasp, but a 2-2 draw in Germany keeps them on course for the knockout stage.
It is possible that victory over Montpellier on Matchday Five will see Arsenal through, and Wenger is looking for his side to secure their safe passage through Europe's premier club competition as quickly as possible.
He said: "The group is open. I believe we are of course in a position where you want to win our home game.
"If we win, we have a 50 per cent chance to be through because Schalke plays Olympiakos here. They are in a position where they have absolutely to win that game as well.
"It will of course depend on our result first against Montpellier and then we will see what happens here.
"It could go to the last game; we could, with luck, do it in the next game. Anyway, we are in a position where we must win against Montpellier."
Wenger believes Arsenal should be two points closer to achieving their goal, with debateable decisions having gone against them against Schalke.
The French tactician was clearly irritated by referee Nicola Rizzoli's decision not to award a foul in the build-up to Klaas Jan-Huntelaar's goal and also for booking Lukas Podolski, who was frustrated at the decision to halt the game due to an injury as Arsenal pressed forward in the second half.
Asked about the first incident, he said: "Yes, (it was a foul) on (Theo) Walcott and he gave the foul against Walcott.
"I invite you to see it again. It is a foul from (Ibrahim) Afellay on Walcott, 100 per cent."
Wenger added: "I must say there was another decision that was absolutely amazing.
"It was the first time I saw that in my long experience, to stop the game when a player has rolled over on his ankle. I have never seen that when you have a goal chance."