Japan coach Norio Sasaki believes mental fortitude and strength will be the key when the defending champions face Australia in the quarterfinals of Women's World Cup on Saturday.

Australia came through a tough Group D that included traditional powerhouses the United States and Sweden, taking second place before pulling off a stunning upset of championship candidates Brazil in the round of 16.

The Matildas also have the added incentive of exacting revenge over Nadeshiko Japan for their 1-0 defeat in the Women's Asian Cup final in Vietnam in May last year.