Ayumu Goromaru (Getty Images)
Cape Town - Japan stormed to a 26-5 victory over Samoa in their Pool B clash at Milton Keynes on Saturday.
As it happened: Japan stun Samoa
Japan led 20-0 at half time.
Japan took the led after Ayumu Goromaru knocked over a seventh minute penalty.
In the 23rd minute, South African referee Craig Joubert awarded Japan a penalty try after a scrum infringement which Ayumu Goromaru successfully converted.
Samoa's ill-discipline cost them with three players receiving yellow cards during the encounter.
Goromaru's educated boot added another penalty before Akihito Yamada scored on the stroke of halftime - Goromaru made no mistake with the conversion.
Goromaru slotted two further penalties in the second half.
Samoa finally got onto the scoresheet in the 63rd minute through an unconverted Paul Perez try.