Fiorentina fired coach Vincenzo Montella on Saturday, the day after a 4-1 home defeat to Roma.
Montella was given a reprieve after a stoppage-time equalizer secured a 1-1 draw against Inter Milan last week but Fiorentina heads into the winter break with five defeats in six matches.
"The decision was taken following a long and detailed analysis of the team's performances and results," Fiorentina said in a statement.
"Given the need to rediscover the necessary grit and determination on the pitch and produce an immediate turnaround, the owners and management decided that a change of coach was the best option."
Montella returned to Fiorentina for his second spell in charge in April but has lost 13 of his 24 Serie A matches.
It is the eighth coaching change in the Italian top flight this season.
