It was the Little Nadeshiko that took command of this Group B contest from the kick-off, starting with a pair of goals from Haruka Osawa.
She scored the match-winner just four minutes in before doubling the lead midway through the first half.
The 23rd-minute strike proved to be a landmark for Japan, as they became the first team to score 100 goals in the competition’s history.
Tomoko Tanaka extended the East Asian’s advantage from the penalty spot on 37 minutes before Sara Ito made it four before the break.
Ito then claimed her second goal of the match with a penalty strike on 55 minutes before Yuzuki Yamamoto wrapped up the scoring with a sixth for Japan in the late stages.
The comprehensive six-goal victory at the Estadio Domingo Burgueno Miguel puts Japan in a strong position to advance to the quarterfinals, while South Africa are still seeking their first win at Uruguay 2018.
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