Inter Milan coach Cristian Chivu leapt to the defence of captain Lautaro Martinez this week.
Tense moments erupted at Appiano Gentile on Wednesday, when Chivu interrupted training to defend Lautaro from an inappropriate comment from the stands.
The Romanian coach, known for his calm demeanor, lost his temper this time and addressed a fan in a firm tone: "Please, respect these people who work.
"I don't want to hear about Sundays or anything else!"
The training session wasn't open to the public, but to a few guests from sponsors and Inter Clubs, says Il Corriere dello Sport.
After Lautaro scored, someone shouted: "Now do it again on Sunday!" A phrase that Chivu perceived as a lack of respect towards the Nerazzurri captain, sparking his reaction, followed by applause from others in attendance.
The incident was over in a matter of seconds, but the identified fan is unlikely to be able to take advantage of similar opportunities in the future.