Massimo Pinca/Associated Press
David Pizarro walked off injured in the opening moments of the second half, and with that it seemed like Fiorentina's chances vanished.
The Chilean is instrumental to the way that Montella's side play, starring as the regista, and when Massimo Ambrosini came on in his place, Fiorentina were restricted in the manner in which they wanted to approach the game.
Borja Valero dropped into the space in front of the back four, and with that, the Spaniard's influence in transition, usually picking the ball up from Pizarro, vanished.
Juve began to press higher, knowing that Fiorentina had to dribble the ball more to dissect their defence, rather than the pinpoint accurate passes from Pizarro.
There are players of a similar ilk, who could be shoehorned into that role, but with Mati Fernandez's injury, and Alberto Aquilani's inconsistent form, Montella was doomed once the 34-year-old exited.