Title holders Serbia and Montenegro lost 82-75 to Nigeria in Group A in the biggest upset of the first day of the World Championships in Japan.
James will play a key role for title favourites the United States
Carmelo Anthony scored 21 points and LeBron James 15 as the United States beat Puerto Rico 111-100 in Group D.
Olympic champions Argentina overcame France 80-70, while Athens silver medallists Italy defeated China 84-69 despite 30 points from Yao Ming.
Meanwhile Lebanon won their Group A opener, beating Venezuela 82-72.
Meanwhile, Dallas Mavericks star Dirk Novitzki scored 27 points as Germany began with a comfortable 81-70 victory over hosts Japan in Group B.
African champions Angola beat Panama 83-70 and Spain blew past New Zealand 86-70 in later games in Hiroshima.
Australia upset Brazil 83-77, European champions Greece overpowered Qatar 84-64 while Turkey produced a surprise 76-74 victory over three-times Olympic bronze medallists Lithuania.
Results from the first round of matches:
Group A: Venezuela 72-82 Lebanon
Group A: Serbia & Montenegro 75-82 Nigeria
Group A: Argentina 80-70 France
Group B: Germany 81-70 Japan
Group B: Angola 83-70 Panama
Group B: Spain 86-70 New Zealand
Group C: Brazil 77-83 Australia
Group C: Greece 84-64 Qatar
Group C: Turkey 76-74 Lithuania
Group D: Puerto Rico 100-111 United States
Group D: Slovenia 96-79 Senegal
Group D: China 69-84 Italy