The Latics take on Maribor in Slovenia on Thursday night knowing only victory coupled with defeat for Zulte Waregem against Group D winners Rubin Kazan would be enough to put them through to the last 32 of the Europa League.
City came from 2-0 down on Tuesday to beat Bayern 3-2 at the Allianz Arena and end the German side's 10-game winning run in the Champions League.
Former City striker Rosler will take charge of his first Wigan game on Thursday after leaving Brentford to succeed Owen Coyle as Latics boss at the weekend.
He said of City's win: "For English football that was very important and also for the club. I think Manchester City will build confidence from that win.
"We are in a position now with an away game and it is still possible to achieve (qualification).
"All our concentration should be on the game (against Maribor). Not on the game on Sunday. We came a long way and we will give everything we have to win the game, then we can only hope for the best."
Rosler watched from the stands on Saturday as Wigan lost at Millwall, their fifth defeat in a row and another blow to their hopes of returning to the Barclays Premier League at the first attempt.
Rosler left striker Grant Holt at home to prepare for Sunday's derby against Bolton but he is expecting good things from the players he does select.
The German said: "The situation is I've had two training days with the team, I watched Saturday from the stands.
"We will play a different team and everybody can impress. I've collected as many impressions as I can get and everybody is playing for their future. I think that is motivation enough."
One player hoping for a start is wideman Roger Espinoza, who starred in Wigan's shock FA Cup final triumph over City but has started just four games this season.
The Honduras international likes what he has seen from Rosler so far, and said: "We're trying to learn as much as we can. I know in the coming weeks there will be a lot of stuff we'll learn and get our style going.
"Any time there is a new manager you know you have to prove yourself and work hard, and I think everybody in the team has been doing that.
"I think what's coming to the team is very bright. He (Rosler) comes with a positive mindset that I think many of us needed.
"Now is like a new beginning again and this is one of those games we need to win and show that positive mentality."
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