Germany tasted defeat in their World Cup opener for the second tournament in a row, as Japan's substitutes completed a sensational turnaround after Ilkay Gündogan's first half penalty.

Hansi Flick's side covered their mouths in the pre-match team photo, in protest at FIFA's stance on ‘One Love' armbands but their football did not do the talking for them.

After Japan had an early strike disallowed for offside, Gündogan put the 2014 winners ahead from the spot, following a clumsy challenge from Japan keeper Shuichi Gonda on David Raum.

While Germany had the better of the opening half marginally, both sides were sloppy in possession at times. Hansi Flick's side asserted a greater measure of dominance after the break, with Jamal Musiala coming increasingly to the fore. The Bayern Munich man spied a great chance after some sensational footwork before Serge Gnabry forced a strong double save from Gonda.

Germany were indebted to a brilliant reaction save from captain Manuel Neuer in the 75th minute but soon after, Neuer could only parry Takumi Minamino's shot in to the path of Ritsu Doan. The Freiburg forward had come on as a substitute only moments earlier, and slammed joyously home. 

Another substitute, Bochum's Takuma Asano, completed the comeback in the 83rd minute with a fine solo effort that took advantage of some questionable Germany defending.

Flick threw on Niclas Füllkrug and Mario Götze in a bid to change the momentum but his side couldn't find the breakthrough. They have it all to do in their remaining games, against Spain on Sunday and Costa Rica on Thursday.

Thomas Müller: 'Shock'

"I'm in shock," admitted Thomas Müller post-match, speaking to German broadcaster ARD. "I'm still a bit baffled because, the way we played, those are the sort of games you nomally win. We were the dominant side and hardly gave anything away either with or without the ball. I felt we played an intensive game.

"But it's difficult to win when you don't take your chances going forward and then concede goals like that at the back.

"Now we need to make sure we shake ourselves off, recover physically and make sure we approach the Spain game to win."