The 28-year-old president called league president Paolo Dal Pino "the biggest and darkest clown I have ever seen".
"You are probably the biggest and darkest clown I have ever seen."
They were the insulting words directed at Paolo Dal Pino, the president of Italy's top football league, Serie A, over his handling of the COVID-19 coronavirus outbreak.
The man behind the Instagram tirade — the president of Inter Milan, Steven Zhang — now faces disciplinary action.
Ten Serie A matches have been postponed over the last two weekends because of the virus outbreak in Italy, the worst-hit country in Europe. The country has seen 50 people die and more than 2,000 infected.
After initially saying that games could be held in empty stadiums, the Italian league decided just hours before kick-off they should be postponed until May.
One of the games was Juventus v Inter and the league's decision to postpone was seen as being driven by the Turin club, who do not want to play a home game in an empty stadium. Juventus and Inter Milan are both vying for the title along with Lazio.
The Italian Football Federation (Federazione Italiana Gioco Calcio) opened an inquiry Tuesday into Zhang's post, AP reported.
To conclude his rant, Zhang called for caution: "Everybody around the world, doesn't matter if you are Inter fan or Juve fan or no fan at all. Please be safe! This is the most important thing for you, your family, and our society."
The Italian Cup semi-final second leg between Juventus and AC Milan (1-1 after first leg), scheduled for March 4, was originally to be played behind closed doors due to the coronavirus epidemic.
Given the magnitude of it, the prefecture of Turin decided to postpone the match.
Inter last week played Ludogorets inside an empty stadium in the Europa League on February, 27, winning 2-1.