A costly defensive mix-up involving Maya Yoshida saw Japan held to a 1-1 draw against Iraq in Tuesday's World Cup qualifying clash.
Yuya Osako's first-half header looked set to give Vahid Halilhodzic's men an important three points in the Group B clash in Tehran, but Mahdi Kamil capitalised on a mistake at the back to give Iraq a share of the spoils.
The result puts Japan a point above Saudi Arabia and Australia ahead of their final two matches against those two teams later this year.
Japan were held to an unconvincing 1-1 draw by Syria in a friendly match last Wednesday but they needed only eight minutes to take the lead at Shahid Dastgerdi Stadium.
Genki Haraguchi's shot was well saved at the near post, but captain Keisuke Honda's resulting corner from the right was glanced expertly by Osako over Mohammed Gassid and into the bottom-right corner.
Kamil and Mohannad Abdul Raheem missed good opportunities to draw Iraq level as Japan began to sit back to defend their slender advantage, although Osako should have done better when he steered wide from point-blank range in the second half.
Their lack of ambition to kill off the match would ultimately cost them, as Kamil made the most of some dreadful defensive play to secure only a fifth point from eight matches for Iraq.
Alaa Abdul Zahra stumbled into the box and, as Yoshida attempted to shield the ball towards Eiji Kawashima, Abdul Raheem's challenge forced the goalkeeper to spill the ball and Kamil was given the chance to drill low into the net.
Honda shot straight at Gassid with Japan's only effort on target of the second half deep into injury time, but there was to be no late drama.
Japan host Australia in their penultimate group-stage game, before visiting Saudi Arabia in what could prove to be a decisive fixture.