China beat Czech Republic 66-57 to win the Olympic women's basketball opener here while the US were stretched by Croatia.
China's Guard Ma Zengyu scored 14 of 16 points in the first half, the veteran Miao Lijie added 12 while Gao Song and Chen Nan chipped in 10 points each, Xinhua reports.
The Asian team finished fourth in 2008 Beijing Olympics.
The victory boosted China's chance of advancing into the second phase as the world runners-up Czechs were tagged as the toughest opponents of Group A except for six-time champions United States.
China now face Croatia, Turkey, the US and Angola in the coming matches. One more Chinese win could help them book a berth in the quarterfinals.
The Czechs scored the game's opening basket but from then on China never trailed.
Eva Viteckova scored 14 points for the Czech Republic while captain Hana Horakova, MVP of the 2012 World Championships, only made two shots of her 13 attempts.
Trailing 16-20 after the first quarter, the Czechs tied at 24-24 midway through the second. China then scored an eight-point margin and carried a 36-29 lead to the break.
China extended the lead to as many as 12 points in the third quarter, but saw the lead cut in the fourth period when Michaela Zrustova's 3-pointer tied it on 53-53 with 7:33 minutes to go.
Chen then ignited a 12-2 run which finally sealed the victory.
"This was our first match and we felt very well prepared," said Ma.
"The Czechs are a very good team but at the beginning we managed to get hold of them and then we managed to show very good teamwork."
Defending champions US overcame a sloppy performance to beat Croatia 81-56 and top Group A.
The Americans struggled for the first quarter before pulling away to win their 34th consecutive Olympic match. The US led 53-49 early in the fourth quarter before a 16-0 run put the Americans on top.
Despite missing their first 14 shots, Croatia hung tough for the first 30 minutes in their Olympic debut. Jelena Ivezic scored 22 points and Marija Vrsaljko added 19.
Angel McCoughtry finished with 13 points for the US. Tina Charles had 14 points and 10 rebounds while Candace Parker finished with 11 points and 13 boards.
It was the second Olympics in a row when the Americans struggled in their opener. They trailed the Czechs 2-13 before winning in Beijing.
In another Group A match, Turkey spoiled Angola's party with a 72-50 victory. Emine Palazoglu led Turkey with 13 points and all but two of their players scored against Angola.
Becky Hammon scored eight straight points to help Russia rally from double-digit deficit in the fourth quarter to beat Canada 58-53 in Group B.
Celine Dumerc's 23 points and five assists helped France come from behind to beat Brazil 73-58.
Trailing 16-20 by the end of the first quarter, France tied the score 34-34 by half and led 52-49 after the third quarter. Brazil was outscored 9-21 in the last quarter.
Australia, runners-up in the last three Olympics, beat Britain 74-58 to top Group B.
Lauren Jackson, who carried the flag for Australian delegation in the opening ceremony, led her team with a match-high 18 points.