Iraq stunned Asian Cup favourites Japan to reach the knockout stages thanks to Aymen Hussein’s first-half double.
Hussein headed the Lions of Mesopotamia into an early lead in Qatar’s Education City Stadium after Japan keeper Zion Suzuki failed to deal with a cross.
And he doubled their lead just before half-time with another header, this time from Ahmed Al-Hajjaj’s cross.
Japan’s goal came in injury time at the end of the game, Liverpool’s Wataru Endo heading in.
This was the first time the Samurai Blue, ranked 17th in the world, had lost to Iraq, ranked 63rd, in 42 years – a run of nine games.
Hajime Moriyasu’s side, who beat Vietnam 4-2 in the opening game, could need a result in their final game against Indonesia to reach the knockout stages.
Iraq, who beat Indonesia last time out, can afford to rest players against Vietnam.
The top two automatically qualify, with the four best third-placed teams also progressing to the last 16.
Hosts Qatar and Australia were the first two teams to seal their places in the knockout stages.
