Germany's soccer federation sacked Hansi Flick as national team head coach on Sunday in the wake of a 4-1 friendly loss to Japan.
Hajime Moriyasu's Japanese side defeated the four-time world champions for the second time in less than a yearon Saturday at Wolfsburg's Volkswagen Arena, having also prevailed 2-1 at the World Cup last November.
While the Group E victory in Qatar was a tense come-from-behind affair, Saturday's friendly was dominated from the outset by the Samurai Blue.
Junya Ito and Ayase Ueda found the net in the first half, while super sub Takefusa Kubo set up late goals for Takuma Asano and Ao Tanaka.
The humbling result proved to be the final straw for the German Football Association (DFB), which is desperate to turn things around ahead of hosting next year's European Championship.
Germany has managed just four wins in its last 17 internationals, with its World Cup loss to Japan leading to a second consecutive group-stage exit from the tournament.
DFB director Rudi Voller will take charge for Germany's next friendly against France in Dortmund on Tuesday.
"Hansi Flick worked incredibly hard over the past few months with his coaching team to try and turn things around after the World Cup in Qatar," Voller said in a statement from the DFB.
"Unfortunately though, he hasn't been able to do so. The Japan game clearly showed us that we couldn't carry on like this."
Japan will face Turkey in a friendly in Genk, Belgium, on Tuesday.