In their Group C opener, the Americans took to the court with all the firepower of Breanna Stewart and A'ja Wilson, who combined to pour in 46 points, and under the leadership of captain Diana Taurasi, who is making her sixth Games appearance in Paris.
Taurasi, 42, said she was happy to be back in Lille, where she often played in the city during her time in the EuroLeague Women, and said that more and more athletes like herself are reaching a stage of long-term in their careers.
"The world of sports has changed a lot and we have many opportunities to improve ourselves physically, how to train and more, that's why we see examples like Rudy (Fernandez) or Lebron (James) and Rafael (Nadal)," Taurasi said.
"It's happening in all sports and it's one thing that will continue with the next generation."
The Japanese, however, showed that they could also dance around the court, capitalizing on seven three-point baskets in the first half by Rui Machida and Mai Yamamoto. At just 5-foot, 7-inches (1.62 m) tall, they proved they can still be dangerous and daring.
Hosts France pulled off a major upset in Group C, after overcoming a first-quarter deficit to beat Canada 75-54.
Fifth-ranked Canada withered under a rally by the seventh-ranked hosts, scoring just two points in the second quarter - the fewest points ever scored by any team in a single quarter at the Olympics, men or women.
French centre Marieme Badiane and forward Gabby Williams were the heroes of the 'allez les Bleues' evening, with the pair receiving a rousing post-match ovation and posing for selfies with the crowd.
On a day of surprises, favoured Belgium got their Olympic bid off to a bad start, losing 83-69 to debutantes Germany in Group B.
Belgium were partly undone by Germany's dynamic Sabally sisters, Satou and Nyara, who poured in 33 points between them.
The second shock of Group B came when Nigeria beat Australia 75-62 as point guard Ezinne Kalu scored 19 points to help 12th-ranked Nigeria, the three-time defending African champions, beat third-ranked Australia.
"Our defence were relentless," Kalu said.
"When we were on court, we smelt blood for the ball. Nobody defends like us, and that's what kept us going," she said, adding: "Second half Australia came out very strong... But we just kept our foot on the gas and kept going."
