The Viola only need a scoreless draw to knock their rivals out of Europe but their veteran midfielder insists that Vincenzo Montella's men remain the underdogs
After claiming a 1-1 draw in the first leg of their last-16 clash with the Bianconeri in Turin last week courtesy of Mario Gomez's late strike, the Viola need only a scoreless draw at the Artemio Franchi to qualify for the quarter-finals.
While Fiorentina upset Juve 4-2 at the same venue earlier this season, Ambrosini thinks it ludicrous that some pundits are making Vincenzo Montella's men the slight favourites to progress at the expense of the Serie A champions.
"In a game that is level, anything can happen," the midfielder is quoted as saying by his club's official website.
"The 1-1 draw leaves absolutely everything unchanged. It would be crazy to think of ourselves as favourites.
"There is a difference [between the two clubs] in terms of a structural and environmental level.
"To compete at the top for more years is what every club wants and we want to play well, to win and reach important targets.
"However, Juventus are definitely one of the strongest teams [in the Europa League]."
If Fiorentina are to prevail, they will need star summer signing Gomez to once again influence the game.
There are those that believe that the former Bayern Munich forward is now back at his best following a lengthy spell on the sidelines with a knee injury, but Ambrosini insists that his top level is yet to come.
"Mario still needs to play a lot of games," the 36-year-old argued. "I saw him in peak fitness in pre-season and he needs more time."
Meanwhile, Ambrosini intimated that he would like to extend his stay in Florence, having joined on a one-year deal following his departure from AC Milan last summer.
"The club knows my desire," he explained. "I am totally satisfied with the decision I made [to join Fiorentina]."