Romelu Lukaku and Marcelo Brozevic squared up in the dressing room and had to be separated, according to reports.
Inter Milan limped to a 1-1 draw with Slavia Prague in their Champions League opener after Nicolo Barrella’s injury-time equaliser.
And La Gazzetta dello Sport claims that after Lukaku criticised the team for not following Antonio Conte’s tactics on Tuesday, Brozovic felt the comments were aimed at him.
Their report adds that team-mates were forced to get between the duo before the furious row escalated further.
Inter take on bitter rivals AC Milan on Saturday as they bid to kick-start their faltering season.
Lukaku has endured a tough time since his £74million escape from Manchester United after being criticised over his weight when he arrived.
The Belgian international was then subjected to vile racist abuse as he prepared to take a penalty against Cagliari.
And Serie A chiefs have decided not to take action over the incident – although the home side were fined for fans throwing bottles onto the pitch.
An Italian commentator has been fired after making a racist remark about Lukaku – suggesting a player should give the striker “ten bananas” to distract him.
Luciano Passirani appeared as a guest on TopCalcio24 and was praising the Inter Milan striker when he made the shocking remarks.
Lukaku has tried to let his football do the talking and has two goals in three Serie A matches.