"Even Australia are suffering in this tournament," Nakamura said after Japan beat the United Arab Emirates 3-1 while Australia crashed to Iraq by the same score on Friday.

"There must be some impact of the heat when a country, which reached the World Cup knockout tournament, are left with one loss and one draw.

"This may be typical of the Asian Cup and it is tough."

Australia's players, many of them European-based, have struggled to get to grips with the sapping conditions in Bangkok and have looked a shadow of the team that beat Japan during the World Cup in Germany last year.

Japan coach Ivica Osim acknowledged how much the weather is playing a part after his team's victory on Friday.

"Most of all, I am happy that it has ended without any of our players and staff suffering a heart attack," he said of the match.

"It was such harsh weather conditions."