Kotaro Matsushima scored a bonus-point try deep into injury time as Japan moved to the brink of their first Rugby World Cup quarterfinal with a 38-19 Pool A victory over Samoa at the City of Toyota Stadium.
The hosts, who turned the tournament upside down when they beat Ireland last week, moved to 14 points with the win and also secured their third victory in the pool phase for the second successive World Cup.
The loss ended the Pacific islanders' chances of their first place in the knockout phase since 1995, although the grouping is not likely to be decided until Japan play Scotland in Yokohama in the last game of the pool phase on 13 October.
Number eight Kazuki Himeno, centre Timothy Lafaele and winger Kenki Fukuoka also scored tries for Japan, while flyhalf Yu Tamura added 18 points with the boot in front of a passionate crowd of just under 40,000.