Ousmane Dembele was axed from Paris Saint-Germain's squad for Tuesday's Champions League clash against Arsenal because he did not "comply with or respect the expectations of the team", coach Luis Enrique said.
It follows reports in French media that the 27-year-old winger had a heated exchange with Luis Enrique following PSG's 3-1 win against Rennes on Friday, in which Dembele was substituted late on.
Dembele has been one of the team's stand-out players so far this season and featured in PSG's Champions League win against Girona earlier this month.
But Luis Enrique, speaking at the Emirates in London on Monday, said the France international had not travelled with the squad from Paris.
"If someone doesn't comply or respect the expectations of the team, it means they are not prepared to play," he said.
"The match tomorrow is very important and I want all my players to be ready, so as a consequence I have left him (Dembele) out. I want the best for my team and that is my job."
The former Spain manager said he was "100%" sure of his decision.
"It doesn't mean this is irreversible, but I took the best decision for the team and that is why I signed here, to create a team that has a strong identity and has a lot of character," he added.
Asked to explain the altercation with Dembele, Luis Enrique replied: "I am very honest and I will be honest, but I am not going to create a soap opera out of this.
"There are no problems between us. That is completely false. This is simply about the responsibilities of the player."
Without the in-form Dembele, who has four goals and as many assists in six league games this season, PSG will rely more heavily on Bradley Barcola.
Barcola is the leading scorer in the French top flight this season with six goals, two of which came in the victory over Rennes.
Luis Enrique praised Arsenal boss Mikel Arteta, hailing his former Barcelona teammate as one of the best managers in world football.
"He is one of the best coaches on the market at the moment," he said. "He changed Arsenal's fortunes from a somewhat winless streak to one of the best teams in the world that is competing for titles.
"I would go as far as to say they are the best team in Europe playing without the ball. He is a great coach and a great person."