Lautero Martinez and Antonio Conte fell out in Inter's 3-1 win over Roma on Wednesday evening.
The Argentine started the game on the bench but was subbed on in the 33rd minute when Alexis Sanchez suffered an injury.
However, Martinez would not play the rest of the game as he was replaced with 13 minutes remaining.
The 23-year-old was absolutely fuming after he was subbed off.
Martinez starred down Conte as he may his way to the bench and kicked a water bottle in anger.
That prompted the Italian manager to turn round and give Martinez a piece of his mind.
According to Sky Sport Italia, per the Daily Mail, Conte shouted to the striker: "Have respect! Who are you angry with? Never react like this again."
Inter assistant manager Cristian Stellini actually praised Martinez for his actions after the game.
"This is an example of the mentality we want to see. Even if the result is already secure, we expect all the players to give the maximum effort," he said.
"At that moment, Lautaro was not playing up to the right standard and we want players who are always fully focused.
"Some things remain on the pitch, it's all in the past now and we will look forward to the next match."
However, this incident did not stay on the pitch.
That's because Martinez and Conte had a boxing match in training to settle their differences on Thursday.
Yes, you read that right. Romelu Lukaku hosted the 'fight' and you can watch the video, posted by Conte himself, below.
The below clip shows Conte jokingly throwing some punches at Martinez before the two posed for pictures.
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That is gold. It just goes to show what a great atmosphere Conte has built at the Serie A winners.