A'Ja Wilson led the way for the United States as they saw off host nation Japan 86-69 at the Tokyo Olympics, while China and Belgium booked their places in the quarter-finals.
Team USA are six-time defending champions, though they were made to work by their opponents in Saitama before their height proved decisive.
Now on a 51-game winning streak at the Olympics, Team USA top Group B on four points from their two games so far at the Games.
Wilson was the top scorer with 20 points, while she also contributed 10 rebounds and three assists. Support arrived from Breanna Stewart (15 points) and Brittney Griner (15 points).
It was by no means a comfortable victory, however, having edged out Nigeria 81-72 in their first match.
"Just communication. One, we're getting used to the ball. And then two, just working on making sure we're just all in for each other and understanding the personnel a little bit better," explained guard Jewell Loyd when asked how the team were looking to improve as the tournament goes on.
"Taking a breath. We've played a little fast in other games so just trying to get a rhythm for us, take it slow and play our basketball."
Only Wilson scored more points than Japan's Maki Takada, but the hosts were simply physically outmatched.
"[Team USA] are really superstars," said Evelyn Mawuli. "They know how to play and they're tall and we're small, so we have to run faster than them. So that was a bit difficult, but it was fun."
CHINA SNATCH LATE WIN TO SEAL QUARTER-FINAL SPOT
China and Belgium are sure of their places in the last eight.
That is because of a last-gasp win for China against Australia, avoiding overtime in dramatic fashion to clinch a 76-74 triumph in Group C.
China, who were led by 20-point Wang Siyu, were 11 ahead at one stage in the final quarter, but that deficit was cut down by a resurgent Australia.
However, with 0.6 seconds left, Li Yueru was fouled under the basket. She made both free throws to seal victory and progression into the quarters.
In the process, Belgium's progress was also secured. They beat Puerto Rico 87-52 in the first of Friday's matches.
GARNIER PROUD OF FRANCE REACTION
Elsewhere, France bounced back from an opening defeat to Japan with an 87-62 victory over Nigeria in Group B.
Five players made into double figures for points for the French team, with Sandrine Gruda topping the charts with 14, adding nine rebounds and three assists.
"It was necessary after the defeat against Japan to have a good reaction. I am proud of my team because they did and they all played very hard defence," France coach Valerie Garnier said.
"This is necessary against Nigeria because they fight a lot. After we did this very good job, we tried to make the biggest gap possible, so 25 points was a good result for us."
There were no excuses for Nigeria coach Otis Hughley Jr, who said: "We just got beaten really bad. Offensively we were flat and we couldn't score. You can't play that way against the number five team in the world."