Flick praised the English Premier League at his pre-match press conference saying “the quality is very high”.
“They have six or seven clubs of almost equal level,” said Flick, a former Bayern Munich coach.
Flick said German players who move to the Premier League “take a step up”.
Flick’s squad contains four players who played for English clubs last season, including three under German coach Thomas Tuchel at Chelsea.
Flick singled out Kai Havertz “who grew up under the influence of Thomas Tuchel.”
Midfielder Ilkay Gundogan, who scored twice on the final day of the Premier League season to seal the title for Manchester City, praised England’s strength in depth.
“They could form three national teams,” he said.
Flick said he was disappointed with a 1-1 draw with Italy in Bologna on Saturday, on the same evening that England lost their goup opener 1-0 in Hungary.
“It is obvious that we must do better” against England, said Flick.
“They have extraordinary players and their game is very physical. (Harry) Kane is a world-class striker, he has a huge quality,” Flick said.
“It will be a big game for us and it will be important to implement our plan well,” said Flick, still undefeated after ten games as Germany coach.
Gundogan, who has been at City since 2016, insisted the historic rivalry between England and Germany was “no longer an issue.”
“The respect is there, and in the end it is about sport,” he said.
“We have had several German players who succeeded in England, and it has become very friendly, even if sometimes we banter a little”.