Japan was tipped as the favorites to win the Asian Cup but a shock defeat to Iraq has exposed cracks in coach Hajime Moriyasu's previously well-oiled machine.
The 2-1 loss leaves Samurai Blue facing a potential last-16 match with South Korea, assuming Japan still qualifies from its group.
Even a draw on Wednesday against Indonesia would allow Japan to progress, but after Friday's reality check against a side ranked 46 places below them, the Samurai Blue will be desperate for a morale-boosting win.