The game with Barnsley comes hot on the heels of Saturday's FA Cup heroics against Cardiff City where an impressive away win has set up a quarter final tie with Manchester City.
However the importance of the league is not lost on Rosler and the game in hand against Barnsley this evening has been dubbed a "must win" game by the Latics boss.
Speaking to the Wigan Evening Post, Rosler said: "I think games like this are the most difficult of all.
"We lost recently against Doncaster, who are in a similar situation to Barnsley. Coming into the game on hte bck of a massive win, at a Premier League club, we must be very careful.
"Barnsley have got a lot of draws lately, which tells me they are very difficult to beat. They will come here and make it a long evening for us, but the most important thing is the result.
"These are the game we simply have to win if we are to make it into the play-offs. We have been playing catch up since I came to the club, an there has not bee much room for error.
"So far, things are going our way - 21 points from 11 games is a very good return - and we must continue. To continue we have go to win all of our home games, starting with Barnsley- it is a must-win game for us."
Victory would move the Latics up to seventh in the table, four points behind sixth placed Reading but with a game in hand.
For more on this story and other Latics news pick up your copy of the Wigan Evening Post from newsagents across the borough priced at 60p.