The Manchester City midfielder conceded the side are not as good as they were in 2018 when they reached the semi-finals of the World Cup but has implored his team to fix mistakes and improve.
Belgium are third in League A Group 2, level on three points with France but will face a tough Italy side next month in what will be a huge test for the national side.
De Bruyne said his team-mates know "what went wrong" during an exchange at half-time and spoke to Belgian broadcaster VTM about how the side will never win anything if they perform like they did last night.
"I cannot repeat that in the media but it has to be better in every way," said the 33-year-old.
"If the standard we want to reach is the best, but we're no longer good enough to get to that level, then you have to give everything.
"If you don't even do that, it's over."
He highlighted the defence as a weakness and how the structure of the team affects their style of play.
"If you stay with six at the back, there is no connection," he added. "It is what it is.
"It is not about transition, but about people who do not perform their tasks."