Japan survived early pressure from Zico's Iraq to beat them 1-0 at home on Tuesday, taking a significant step towards qualifying for the 2014 soccer World Cup in Brazil.
Ryoichi Maeda steered in a point-blank header in the 25th minute for the Asian champions, who lost playmaker Shinji Kagawa to a back strain an hour before kick-off.
Iraq, shock Asian Cup winners in 2007 and now under the stewardship of former Japan coach Zico, could have scored twice before Maeda struck, both times having close-range efforts blocked.
A diving header from Keisuke Honda was brilliantly tipped against the post by goalkeeper Noor Sabri in the second half.
Japan now lead World Cup qualifying Group B by eight points from Iraq, Australia and Oman, at least until Jordan host the Socceroos later on Tuesday.
Alberto Zaccheroni's side have 10 points from four matches in the final round of Asian qualifying.