SAPPORO (Japan), Aug 19: The United States began confidently while Lebanon brought a fragment of joy to their war-torn country on day one of the world basketball championship on Saturday.

Olympic gold medallists Argentina also made a smooth start but defending world champions Serbia & Montenegro fell victim to a run-and-gun Nigeria team in the first big upset in Japan.

Carmelo Anthony scored 21 points as the US produced an efficient 111-100 win over Puerto Rico in their Group D opener.

Fellow co-captain LeBron James added 15 points as the tournament favourites recovered from a slow start in Sapporo.

Lebanon's players were forced to endure an arduous bus journey through bombed-out villages into Syria and Jordan to escape Israeli air strikes before arriving in Japan.

But they looked sharp in their opening Group A game in a convincing 82-72 victory.

New York Knicks guard Ime Udoka grabbed 18 points as Nigeria's tenacious defence and open-court speed brought a deserved 82-75 win over Serbia & Montenegro in Group A.

Argentina avoided an early slip-up against France, San Antonio Spurs guard Manu Ginobili hitting 22 points in a solid 80-70 win in the evening game in Group A.

Olympic silver medallists Italy overcame a rampant Yao Ming in an 84-69 victory over China and Slovenia underlined their credentials as potential dark horses with a 96-79 win over Senegal in Group D.

Meanwhile 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 in Group C with C.J. Bruton scoring 16 points and Sam Mackinnon 15 for the Boomers.

European champions Greece overpowered Qatar 84-64 while Turkey produced a surprise 76-74 victory over three-times Olympic bronze medallists Lithuania in the other Group C games.—Reuters