Substitute Kaoru Mitoma scored twice in the dying minutes as Japan beat Australia 2-0 on Thursday to book their place at a seventh straight World Cup and in doing so also helped Saudi Arabia qualify.
It was a crushing blow for an understrength Socceroos who now face a perilous play-off to keep alive their hopes of making Qatar.
The game in a wet Sydney looked destined for a draw before Mitoma converted from close range on 89 minutes, and then again after a mazy run in injury time to spark joyous celebrations from the visitors.
Victory pushed Japan to the top of Asian Group B qualifying on 21 points, six clear of Australia with only one more game to play.