TOKYO — Known for their towering drives, Bryson DeChambeau and Jon Rahm won't make it to the tee box at the Olympics.

The past two U.S. Open champions became the best-known athletes to drop out of the Tokyo Games on Sunday after testing positive for COVID-19.

DeChambeau's positive came before he left the United States for Tokyo. The musclebound American famous for his game-changing swing speed will be replaced by Patrick Reed.

“I am deeply disappointed not to be able to compete in the Olympics for Team USA,” DeChambeau said in a statement. “Representing my country means the world to me and it is was a tremendous honor to make this team.”

Rahm was flagged for COVID-19 for the second time in two months — he had a six-shot lead at the Memorial in early June when he was forced to withdraw because of a positive test.

The U.S. men's basketball team lost in the Olympics for the first time since 2004, dropping its tournament opener against France 83-76.Evan Fournier's 3-pointer with just under a minute left put France ahead to stay, leaving the Americans' quest for a fourth consecutive gold medal in serious trouble. France also knocked the U.S. out of contention in the Basketball World Cup two years ago.The U.S. had won 25 consecutive Olympic games, last losing at the Athens Games 17 years ago and settling for a bronze medal there.The loss doesn't knock the U.S. out of medal contention, but it essentially eliminates the margin for error. The Americans play Iran on Wednesday and then the Czech Republic on Saturday in its final two Group A games; win both of those, and the U.S. will be in the quarterfinals.

No Michael Phelps, no problem for U.S. swimming.The powerhouse Americans collected six medals — including a gold for Chase Kalisz in the 400-meter individual medley — in the first session of finals. During Phelps' record-setting career that spanned five Games, the U.S. never won that many medals in the first batch of events.“A pretty good start for the U.S.,” said Kieran Smith, who snagged a bronze in the men's 400 freestyle.