SAITAMA, Japan, July 27 (Reuters) - The United States overcame a slow start to top a stubborn Nigeria 81-72 on Tuesday, beginning their quest for a seventh straight gold medal in Olympic women"s basketball. The U.S. women found themselves in uncomfortable territory at the Saitama Super Arena as the Nigerians led 20-17 after the first quarter, pressuring the Americans into committing eight turnovers. The U.S. women regained their footing and took the lead halfway through the second quarter on a Diana Taurasi three-pointer that was part of a 23-0 run en route to a 44-32 U.S. advantage at halftime. Refusing to go away, Nigeria cut the deficit, which was as much as 22, to eight points with just over three minutes left to play, before the U.S. again steadied the ship with two quick baskets after a time-out. A"ja Wilson, the WNBA"s most valuable player in 2020, led the United States with 19 points. Brittney Griner chipped in 13 and Taurasi, competing in her fifth Olympics, added 10 points. Veteran U.S. captain Sue Bird gave credit to Nigeria for the defensive pressure they brought but took heart in the way her team was able to adjust. "They like to make the game chaotic, they like to make you do things that you"re not used to doing, play a way you don"t want to play. It"s never going to be pretty against them," she said. Nigeria had four scorers in double digits led by Ezinne Kalu with 16 points. Their captain Adaora Elonu took away positives despite coming up short. "It"s a mix of disappointment but also encouragement for us because we wanted some rhythm and we got that toward the end. So if we can carry that on for the next game it will be good," she said. JAPAN GETS BY FRANCE In the day"s earlier Group B game, hosts Japan battled to a 74-70 win over France with a gritty defensive display and ruthless three-point shooting. France struggled to get into their offence as the hosts looked to trap their ball handlers with double and triple teams, while Japan capitalised on French defensive lapses by knocking down a series of clutch three-pointers in the final frame. The French briefly took the lead, making a run in the fourth quarter, followed by a back-and-forth final few minutes, until Moeko Nagaoka sank a dagger three-pointer with 29 seconds left to put Japan up 72-68. Japan had three scorers in double digits including Nagaoka, Maki Takada, and Saki Hayashi with a team-high 12 points, while Sandrine Gruda led France with a game-high 18 points and grabbed nine rebounds. Japan"s Saori Miyazaki said aggressive defence was key to her team"s game plan. "When it comes to guarding, we"re a lot smaller than the French players. Defence has long been a big part of Japanese basketball and I"m glad it succeeded today," she said. The Japanese made 11 three-pointers, including five in the fourth quarter, to go 41% from behind the arc compared with just 21% for France. "This team of Japan, each time you did a mistake on defence, they shoot a three-pointer and they score," said French head coach Valerie Garnier. In other games, Olympic debutante Belgium beat regular medal contender Australia 85-70 and China eased past Puerto Rico 97-55 in Group C. The teams will be back in action on Friday with Japan facing the United States and France taking on Nigeria, while Belgium will meet Puerto Rico and Australia will play China.