Australia delivered a patchy performance ahead of their quarter-final with England, beating Canada 37-6 in Bordeaux on Saturday.
Japan will remain winless, and unless Canada beat Australia, they will too, after the teams fought out a thrilling 12-12 draw on Tuesday.
Fiji's match against Wales ought now to decide the runner-up position in Pool B after the Fijians struggled to beat Canada 29-16.
Wales got their World Cup trail off to a fine start on Sunday, beating Canada 42-17 in Nantes, although they had to fight back to do it.
