The Italian took over the London side from Slavisa Jokanovic this week, and in an unusually frank interview, insisted that he will not be performing any miracles at Craven Cottage.
Of course, Ranieri will be forever remembered for guiding Leicester City to an historic Premier League title in 2016.
Yet the new Fulham boss was keen to highlight that the club needs to be realistic and work hard in order to remain in the top flight come the end of the season.
Ranieri insisted that Fulham cannot solely wait for a miracle if they hope to be a Premier League club next season.
Fulham sit rock bottom of the league, with only 5 points from 12 matches played so far this season, and their new manager knows that he faces a tough task to rejuvenate their fortunes.
in an interview with 'Sky Sports', Ranieri said: "We have to work hard. That was a bonus, a fairytale. Forget it. Now it is important to not think about miracles."
He continued: "There will be a lot of battles. It is important to be ready together - the club, the players, the fans, all together. They have to support us in the bad moments. This is a bad moment."
Ranieri's first match in charge will come after the international break, when Fulham host fellow strugglers Southampton at Craven Cottage.