Lautaro Martinez is facing disciplinary action at Inter Milan.
Il Corriere dello Sport says Lautaro celebrated his girlfriend's birthday at a local nightclub in the aftermath of defeat to Juventus. While the function had been organised well in advance, management remain "irritated" over Lautaro's decision to hold the party.
Along with management, senior teammates were also left unimpressed.
Lautaro was called in to explain himself yesterday, where it's understood he accepted he had made a mistake.
Inter management are now weighing up whether to sanction the Argentine.