The Gunners were beaten 3-1 at Emirates Stadium in the first leg last month and travel to Germany for Wednesday's return game with a mountain to climb.
Gervinho is under no illusions about the size of the task facing Arsenal but says a surprise comeback is possible if they can get off to a good start.
"We know it is not going to be an easy match. It is not easy to come back from 3-1 against Bayern Munich," the Ivory Coast forward said in the Daily Star.
"They are one of the best teams in the world with good players all over the pitch, so we are expecting a tough game, but we must remain confident.
"We scored at the Emirates against them and you never know, a miracle can happen. If we score an early goal it will put them under pressure.
"We just need to keep positive and give everything we have. We all know anything can happen in football."
The Champions League is Arsenal's last chance for silverware this season after a disappointing domestic campaign, but Gervinho remains confident of overturning the deficit against Bayern.
He said: "This is a completely new match. We are only at half-time in this tie, and we must go there with belief.
"The players will go and give absolutely everything. We have to believe in our talents.
"Personally, I still believe we can make it. I know it will be difficult, but I still believe in us.
"We are going through a tough period at the moment. But there is still a really good spirit with this group."
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