South Africa started their Olympic Games campaign with a 1-0 defeat to hosts Japan in their opening Group A encounter at the Tokyo Stadium on Thursday afternoon.
Tercious Malepe led the team against the host nation, while Reeve Frosler was thrown straight into the starting lineup after arriving for camp on Tuesday following his participation in the Caf Champions League final for Kaizer Chiefs.
South Africa got off to a slow start as they tried to find their rhythm in the game, while Japan dominated proceedings in the opening exchanges of the match.
Japan had a chance to open the scoring after 15 minutes but Takefusa Kubo fired his effort straight into the side-netting.
Ronwen Williams was then called into action at the half-hour mark when he produced an impressive save to deny Koji Miyoshi's goal-bound effort in a one-on-one situation.
The hosts thought they had taken the lead in the 33rd minute when Daichi Hayashi slotted the ball into the back of the net from close range, but his effort was flagged for offside.
Neither team could be separated in the first half as the game went into the half-time break locked at 0-0.
The home team picked up where they left off in the first half and nearly took the lead early in the second half but Kubo again hit the side-netting with his effort from just inside the box.
Williams came to his side's rescue in the 55th minute when he made a point-blank save to deny the hosts an opening goal.
Japan's persistence paid off in the 71st minute as they finally broke the deadlock when Kubo beat his marker before firing his effort past the South African shot-stopper to make it 1-0.
David Notoane opted to bring on fresh legs in the 78th minute when Kobamelo Kodisang was brought on in place of Reeve Frosler.
South Africa had an opportunity to level matters from a free-kick in stoppage time but Teboho Mokoena fired his effort high and wide of the target as Japan held on for the win in the opening Group A match.
