The reigning African champions struggled to cope with the pace, movement and clinical finishing of the world's fifth-ranked side, who punished a series of defensive lapses to secure a comfortable victory ahead of next month's CAF Women's Africa Cup of Nations (WAFCON) finals in Morocco.

Japan wasted little time asserting their dominance, opening the scoring after just two minutes through Kiko Seike. The forward capitalised on hesitant defending to give the hosts the perfect start before doubling her tally in the 18th minute as Banyana found themselves under sustained pressure.

Despite trailing by two goals, South Africa showed glimpses of attacking intent. Noxolo Cesane came close to reducing the deficit in the 22nd minute when her effort drifted narrowly wide, while Gabriela Salgado forced a save from Japanese goalkeeper Ayaka Yamashita shortly afterwards.

However, the hosts continued to dictate proceedings and extended their lead before halftime. Veteran midfielder Momoko Tanikawa unleashed a powerful strike from outside the penalty area that left goalkeeper Andile Dlamini with no chance as Japan moved 3-0 ahead.

Banyana attempted to respond through a move initiated by Cesane, but Nthabiseng Majiya's effort lacked the power needed to trouble Yamashita. The South Africans went into the break searching for answers, while Japan looked dangerous every time they ventured forward.

The second half followed a similar pattern, with the hosts maintaining control. Aoba Fujino made it 4-0 just four minutes after the restart before completing her brace in the 60th minute to put the result beyond doubt.

Linda Motlhalo nearly pulled one back for South Africa three minutes later with a long-range effort, but Yamashita produced another save to preserve her clean sheet.

Head coach Desiree Ellis introduced several substitutions, including former African Women's Player of the Year Thembi Kgatlana, but Banyana were unable to breach Japan's organised defence. Bongeka Gamede produced a crucial block late on to prevent a sixth goal.

The two sides will meet again on Tuesday, with Banyana hoping for a much-improved display in the second friendly.

Mamelodi Sundowns coach Miguel Cardoso: We need as many points as possible, as quickly as possible