AC Milan fired Massimiliano Allegri and put former assistant coach Mauro Tassotti temporarily in charge on Monday, a day after an embarrassing 4-3 loss at promoted Sassuolo.
Languishing in 11th place, Milan announced the move on its website.
Milan has won only five of 19 matches this season and Allegri had already announced over the winter break that he would leave at the end of the season. But the loss to Sassuolo, which got four goals from teenage forward Domenico Berardi, hastened his departure.
The Sassuolo game marked the debut of recently signed forward Keisuke Honda and Milan was hoping that the Japan international would lead the squad to a second-half surge the way Mario Balotelli did last season.
But as soon as the match ended, Milan general manager Barbara Berlusconi said the loss highlighted the need for urgent change.
Allegri took over Milan in 2010 and won Serie A in his first season, then finished second and third the past two years. Still, he never became a favourite of club owner Silvio Berlusconi.
However, Milan was the only Italian club to reach the knockout stage of this season's Champions League and will face Atletico Madrid next month.
The 53-year-old Tassotti is a long-time Milan assistant who had a 17-year playing career with the club.
Former Milan striker and current Milan youth squad coach Filippo Inzaghi had been linked with a caretaker position until the end of the season and it wasn't clear yet how long Tassotti would remain in charge.
Clarence Seedorf and Italy coach Cesare Prandelli are among those who have been mentioned as possible full-time replacements for Allegri.
The 37-year-old Seedorf is currently playing for Botafogo in Brazil, but has indicated he would like to coach when his playing career is over. Prandelli's contract with Italy expires after this year's World Cup.
Allegri's contract was due to expire at the end of this season.