James is putting in influential performances as the US impress
Unbeaten United States edged away at the top of Group B with an impressive 119-82 win over world champions Spain.
LeBron James scored 18 points for a US team packed full of NBA stars who should face the fourth-placed team from Group A in Wednesday's quarter-finals.
Dwayne Wade and Carmelo Anthony also scored 16 points apiece as the US made 48 per cent of its three-pointers to hand Spain its first defeat in Beijing.
Elsewhere, Yao Ming helped China to a thrilling 59-55 win over Germany.
That result is now likely to put the hosts on course for a second straight appearance in the medal round after losses to the US and Spain.
"I'm very happy for the players," said China's Lithuanian-born coach Jonas Kazlauskas.
"It was a difficult game psychologically. We played at home and had to win."
From a neutral's perspective, all eyes were on the clash between Spain and Team USA, seeking to make amends for a disappointing bronze medal at the Athens Games along with poor showings at the 2002 and 2006 World Championships.
Eight US players reached double figures, with Chris Paul adding 14 and Kobe Bryant 11, while the defence forced 28 turnovers and grabbed 16 steals.
"I liked our defence. Forcing the number of turnovers we did was the most satisfying for me," said US coach Mike Krzyzewski.
China's towering centre Yao scored 25 points and grabbed 11 rebounds in keeping his team's hopes of a first-ever Olympic basketball medal alive as they beat Germany.
Their win virtually assures China of advancing to the medal round, where they are likely to face either Lithuania or defending champions Argentina.
In Saturday's other Group B match, Greece beat Angola 102-61 to all but ensure the Athens 2004 silver medallists another trip to the medal round.
In Group A, Lithuania beat Croatia 86-73 and Australia beat Russia 95-80, while Manu Ginobili scored 32 points to lead Argentina to a 97-82 victory over Iran.
Final preliminary round matches will be played Monday.