Team USA had complete control of the game from start to finish and the margin of victory was something they desperately needed after a dramatic finish against Turkey.
While Kemba Walker played consistently well, scoring 15 points with eight assists, Jaylen Brown emerged as a breakout star by adding 20 points with seven rebounds.
Gregg Popovich's side should face a tougher challenge when they take on Greece and reigning NBA MVP Giannis Antetokounmpo in their first second-round match on Saturday.
USA started fast and did not look back. They scored the first 13 points of the game and held Japan scoreless until the middle of the first quarter.
Boston Celtics duo Jayson Tatum and Marcus Smart were sidelined due to injuries, but USA responded by sharing the ball.
All 10 players scored for Popovich's team, with Brown leading the way followed by Walker and Harrison Barnes, who had 14 points with eight rebounds.
Rui Hachimura, selected ninth overall in the 2019 NBA Draft by the Washington Wizards, did not live up to expectations for Japan as he scored four points on two-of-eight shooting. Yudai Baba (18) was the only player in double figures for Julio Lamas' men.
However, Hachimura had a few highlight moments where he stole the show, including a dunk over Myles Turner in the third quarter.
Japan scored just eight points in that period and although they matched USA's tally in the final quarter, an upset was already well out of reach.