The Japan Under-23 national team lost 2-1 to the Paraguay U-21s in the opening match of the Toulon Tournament.
The opening goal was scored in the 18th minute by Pedro Baez in the 18th minute after capitalising on an error by defender Sai van Wermeskerken.
Sanfrecce Hiroshima striker Takuma Asano levelled the match at 1-1 midway through the first half, but the match was eventually decided by Sergio Diaz’s game-winner in the 75th minute.
Makoto Teguramori’s men will next face Portugal on May 23.