By Stefan Coerts, Goal.com
The 51-year-old trainer replaced the Serbian youngster after only 32 minutes of play when Fiorentina was 2-0 down, and Ljajic was not impressed with Rossi's decision.
The Serbia international sarcastically applauded his coach while making his way to the bench, thus infuriating the Fiorentina boss. Rossi pushed the 20-year-old against the back of the dug-out before aiming a punch at Ljajic.
The pair was then split up by other staff members and substitutes before things got out of hand any more than they already had, but Fiorentina has nonetheless decided to let go of Rossi.
"I have decided to fire the coach for what we see as a serious incident. I am sorry for Delio Rossi, because he's a good person. This is a serious matter, though. We will further talk about this tomorrow," club president Andrea Della Valle said of the decision to let the manager go.
Fiorentina eventually managed to salvage a 2-2 draw in the remaining 60 minutes of the game courtesy of two goals from Riccardo Montolivo.
Follow @GoalUSA on Twitter.