Keisuke Honda and Shinji Kagawa helped engineer Japan’s 4-0 rout of tournament newcomer Palestine and Iraq edged Jordan 1-0 yesterday as the last two winners of the Asian Cup claimed victory in their Group D openers.

There’ll be little time for celebration, though, with Japan and Iraq meeting Friday in a match that will likely determine which team tops the group.

Defending champion Japan took a 3-0 lead in the first half with goals from Yasuhito Endo, Shinji Okazaki and Honda’s penalty in wet and windy Newcastle, Australia. Maya Yoshida scored after the break from Kagawa’s cross.

“In modern football it’s not easy to win by four goals,” Japan coach Javier Aguirre said. “So as for tonight’s result I am happy by winning by four goals.”

Japan has won four of the last six Asian Cups and is seeking an unprecedented fifth title. Iraq was a surprise champion in 2007, when the tournament was co-hosted in four south-east Asian countries.

Younis Mahmoud, the star of that tournament, returned to lead Iraq in Brisbane, but lacked match fitness and was replaced just a few minutes before Swindon midfielder Yaser Kasim scored the winner with a deflected shot in the 77th.

“We treated this game like a final,” Kasim said. “It was very important to get the win. The boys are very happy, we just have to calm down and look forward to the second game.”

Iraq’s last group match is against Palestine, giving Iraq the seemingly easier run after the big match against Japan.

A small group of Palestinian fans waved flags, beat drums and sang throughout yesterday’s match.

“The feeling has touched our emotions,” Palestine coach Ahmad Alhasan said. “This is the only national team that plays in this tournament that is still under occupation.”