AC Milan's lack of unity on the field was plainly reflected off it when two players almost came to blows on the bench.
Franck Kessie was visibly upset after being replaced by Andrea Conti in the 69th minute of Sunday's 3-2 derby loss to Inter Milan. The Ivory Coast international then grew even angrier and had to be held back by his teammates after Lucas Biglia said something to him.
Milan coach Gennaro Gattuso said he was disappointed by the incident but managed to crack a small joke after the match.
"Luckily I didn't see it because I was focused on the match, otherwise I would have probably thrown myself in the mix, too," said Gattuso, who was known as a tough, no-nonsense defender during his playing days.
"We lost on the field as well as off it," he said. "This hurt me because it means that someone hasn't understood what I believe in. For me, it's a big defeat on a professional level."
Kessie and Biglia both spoke to the media after the match and publicly apologized.
"I got it wrong because I should have understood the situation after he was replaced," Biglia said. "I wanted him to understand that what he did wasn't the right thing as it pertained to his teammate coming on. We've cleared things up and have talked in the changing room.
"I am sorry to the fans, the club, my teammates and the coach ... It was a bad moment, and now we have to look ahead."
It's not clear what Biglia said to Kessie, but the Ivorian also expressed regret for the incident.
"I apologize to Lucas," Kessie said. "He's older than me, and I apologize also to the fans and the coach."
Milan had been favored to win the match after a run of five straight league victories but there was little evidence of the good play on display on Sunday. The team appeared strangely disjointed, and top scorer Krzysztof Piatek received hardly any service during the match.
Milan's defense, which has been so resilient of late, also looked shaky with goalkeeper Gianluigi Donnarumma and captain Alessio Romagnoli to blame for Inter's first goal in the third minute.
The three goals Milan conceded were as many as it had allowed in its previous 10 matches.
Inter moved third in the Serie A standings, two points above Milan and six ahead of fifth-place Roma. The top four teams qualify for next season's Champions League.