Colombia international Ospina has been Arsenal's cup goalkeeper of choice over the past two seasons but his Champions League campaign last term was marred by him dropping a corner over his own goalline in the group-stage defeat to Olympiacos.
That saw regular number one Petr Cech restored for the first leg of the tie against Barcelona in the knockout stages, with the 28-year-old coming back for the return at Camp Nou where a 5-1 aggregate loss was completed.
This time around, Ospina helped Arsenal through an unbeaten group stage with relatively few alarms and Wenger told a pre-match news conference at the Allianz Arena that he would not revert to Cech again.
"I have nothing to hide there, it will be Ospina because of the quality of his performances," he said when quizzed over the identity of his starting goalkeeper.
"We are in the last 16 because we finished top of the group. If you analyse his performances in every single game, we are where we are down to his great performances."
Wenger would not offer a similar guarantee to out-of-form playmaker Mesut Ozil, on the grounds that he wishes to keep Bayern guessing over his outfield team selection, although he expects the Germany international to relish the chance of impressing in a showpiece fixture in his homeland.
"It's not the best moment to give you the first XI tonight. I will pick the team tomorrow morning and you will see," he added.
"We are playing in Germany, so I am sure Ozil is highly focused to have a good performance tomorrow."
The Barcelona defeat marked the sixth consecutive season Arsenal have bowed out in the last 16 and, with their Premier League title chances fading, they are in the familiar position of hoping history does not repeat itself.
Nevertheless, Wenger was bullish and pointed towards the potential edge of having the second leg at Emirates Stadium.
"Thank you for reminding me of bad history but let's focus on the future," he said.
"I think we have just to focus on the performance. I know we are playing Bayern who, listening to you, are favourites.
"We have to be very positive on the fighting front and the playing front be at the level required.
"It is an advantage to play the second leg at home but we know every minute of tomorrow's game will have a big influence on our chances at home to knock them out."