Japan has made it through to the knockout phase of the Women's World Cup with the minimum of fuss, but the reigning champions will have to move up a gear if they are serious about defending their title.

Japan began its campaign with a 1-0 win over Switzerland last Monday before beating Cameroon 2-1 four days later to clinch a place in the last 16 regardless of the outcome of Tuesday's final group game against Ecuador. Japan's craft and class was apparent in both matches, but there are still rough edges to smooth out before the tournament reaches a stage where opponents do not allow mistakes to go unpunished.

"The team deserves credit for winning two difficult games while dealing with the expectations of defending the title," wrote former Nadeshiko defender Kyoko Yano in Sunday's Nikkan Sports. "But the truth is that some aspects of their play are not going well. It's important to get to the root of the problem before the knockout round starts.