Vahid Halilhodzic was left bewildered as to how his Japan side failed to score in Tuesday's 0-0 draw against Singapore.
Japan, ranked 102 places above their Group E opponents, created a plethora of chances in Saitama in their World Cup qualifying opener.
However, Singapore goalkeeper Mohamad Izwan bin Mahbud was in superb form, making particularly fine saves from Shinji Okazaki and Keisuke Honda in the second half.
Honda did beat Mahbud with a sweetly hit free-kick, but the Milan midfielder saw his effort cannon off the crossbar as Japan were left frustrated.
"I've never seen a situation like this before in my career," head coach Halilhodzic said.
"We kept creating chances and the players gave everything to get the win. The only thing that was missing was a goal.
"If we had been able to get a goal, then it would have turned out to be a different game. It's difficult to accept but there is no need to be despondent."
Captain Makoto Hasebe felt Japan paid the price for failing to play at a high enough tempo.
"At home, in front of great support like this, we have to win," he said.
"When you play against a team that is well organised like tonight, you have to play faster than we did. We've only just started and we need to take the frustration from tonight and use it to our advantage."
