Why do the World Cup champions lose their first game?

A few days ago, the twenty-first World Cup began and Germany, the 2014 World Cup champion, debuted with a defeat against all odds. Mexico stood up to the champion and fought for this result from the very beginning.

3 teams who won the World Cup despite not winning their opening match

Real Madrid go into World Cup mode and lose their first game in

Why do the World Cup champions lose their first game?

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