Leroy Sane has been accused of not caring if he wins or loses by German team-mate Toni Kroos.
The Manchester City winger was axed from Germany’s World Cup squad and even dropped by club boss Pep Guardiola last weekend.
Real Madrid legend Kroos, who also laid into race-row star Mesut Ozil, says Sane has to shape up.
Kroos rapped: “You can look at him and not know if he has won or lost, that it doesn’t seem that important to him.
“It’s about body language and he has to improve this.
“Leroy was fantastic for City last year but Pep has the same problem at the moment — he’s trying to get the best out of him so he can perform better.
“That was why he left him out of the team last weekend, to get him to perform better. If he performs, he’s a real weapon, honestly.
“Leroy has everything you need to be world-class but sometimes you have to tell him he has to perform better.”
Sane, 22, has been recalled for tonight’s Nations League game with France in Munich.
Kroos added: “He is a quality player. We don’t have that many players with his talent.”
Arsenal star Ozil has quit the national team, accusing German FA president Reinhard Grindel of racism.
But Kroos declared: “When it comes to what was said about our FA and the president, I don’t agree with that. I totally reject it. It was not the right criticism.”
Coach Joachim Low said: “There has never been any form of racism among our players to any player from a migrant background.”