Japan booked a ticket to the knockout stage of the Asian Cup in the United Arab Emirates on Sunday with a 1-0 win over Group F opponent Oman, but the four-time champion was once again less than convincing.

Relying on a first-half penalty from Genki Haraguchi, Hajime Moriyasu's side never looked settled despite creating several chances and dominating possession at Abu Dhabi's Zayed Sports City Stadium.

The result followed a 3-2 win over Turkmenistan on Wednesday — another shaky display against an opponent Japan was expected to beat comfortably.