The Latics take on Maribor in Slovenia on Thursday knowing that, like their opponents, only victory coupled with defeat for Zulte Waregem against Group D winners Rubin Kazan would see them progress.
Wigan had been in a good position in their first European campaign after beating Maribor at the DW Stadium and then holding Rubin to a draw but a home defeat to Zulte two weeks ago put the Belgians in pole position.
It was one of three defeats in a week for the FA Cup winners that spelled the end of Owen Coyle's reign after less than six months in charge.
Chairman Dave Whelan moved quickly to replace Coyle, with former Manchester City striker Rosler leaving Brentford to take over at the DW Stadium on Saturday.
He had a watching brief that day as Wigan slumped to a fifth successive defeat at Millwall, leaving them 14th in the Sky Bet Championship table and nine points off the play-off places.
On Monday Rosler made it clear promotion back to the Barclays Premier League was his major priority, but he insisted that will not be at the expense of winning on Thursday.
The German said: "It's a great opportunity for me to see players in a competitive environment where they can show themselves and can impress me. Our motivation should be and will be very high.
"We owe that to ourselves, we are professionals, and we owe it to the supporters who have come a long way to Slovenia supporting us. It's a great opportunity, with a little bit of luck, to progress.
"We don't have it in our own hands, we are dependent on other people, which is not the situation we want to be in.
"Both teams have to play, both teams can progress and we have to make sure we do our own work in terms of winning the game."
- Sports & Recreation
- Rubin Kazan
- Owen Coyle
- Zulte Waregem
- Barclays Premier League