Laurent Blanc chastised suspended Serge Aurier for punishing Paris St Germain with the disparaging remarks he made about his head coach and team-mates ahead of Tuesday's Champions League clash with Chelsea.
The right-back has apologised after a live question-and-answer session on Periscope came to light in which he insulted Blanc and several PSG players.
Aurier was on Sunday suspended for the last-16 first leg at Parc des Princes and faces further disciplinary action.
PSG told the media Blanc would answer only one question on Aurier at Monday's pre-match media conference, but the former France boss returned to the subject time and again.
"How did I react? Very badly," Blanc said.
"This is a democracy, we are free to think what we think, we can have our own opinions.
"(But) that guy, that boy... two years ago I committed myself to make him come to Paris and I think what I saw yesterday that's all the thank you I got. I think that's pitiful.
"I won't say more, because we're here to talk about the Chelsea game."
But a visibly irritated Blanc continued, although he declined to address a question on his authority over the dressing room.
He added: "He's a boy that should be preparing today for a last-16 game of the Champions League. That would've been better instead of staying at home not knowing what to do.
"The player is a big boy, he can do what he wants, but he's penalising the club through the image he gives and what he said."
Blanc promised to address Aurier directly, not through the media.
"If he's got a problem with me, I won't use you journalists to handle the problem. That's for sure," Blanc added.
Blanc denied the outburst had impacted preparations for another meeting with Chelsea with the clubs being drawn together for a third successive season.
"We would like to have prepared with a little bit more calm, but it's a player that gets out by himself," Blanc added.
"Of course we would prefer to avoid that but the most important thing is tomorrow's Champions League game.
"One player won't play, but for the rest the preparation is the same as usual."
Blanc also dismissed suggestions the incident would not have happened at a more established club, like Manchester United or Barcelona, two sides he played for during his distinguished career.
He was initially blocked by the club's media manager from answering the question, but did so anyway.
"I don't think any club is immune from those things, especially with social media," Blanc added. "We're never safe."
Aurier's place at right-back will be taken by Dutchman Gregory van der Wiel or Brazilian Marquinhos, reportedly a Chelsea target.
PSG were beaten by Chelsea at the quarter-final stage in 2014 on away goals, but won by the same method 12 months ago.
With a 24-point lead at the top of Ligue 1, Blanc knows the success of his club's season will be determined by their progress in Europe.
"We'll be playing at a level we're not used to seeing in our national league," Blanc added.
"Now from a football point of view, people think PSG is able to win the Champions League. That's very good. It means we're on a good path."
Blanc was sitting alongside Marco Verratti, the Italian midfielder who on Monday extended his contract until 2020.
The 23-year-old has been one of the star performers in France's top flight since his arrival from Pescara in 2012.
"I'm very happy to extend my contract. It's another proof of that confidence the club has in me," Verratti said.
He was asked about winning the Champions League, but refused to look beyond Chelsea, who are toiling domestically.
"Chelsea are having a difficult time in the Premier League," Verratti added. "The Champions League for them is a good way of saving their season."
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