TOKYO: Without Simone Biles, America's dominance of women's gymnastics continued on Thursday with a gold in the individual all-around competition for the fifth Olympics in a row.

Sunisa Lee, the youngest member of the team, clinched the U.S. spot in the history books in the final rotation of the floor exercise with a total score of 57.433.

"It's crazy," the 18-year-old Lee told reporters after her win. "It doesn't feel like real life at all."

Lee "absolutely killed it!!! OLYMPIC CHAMPION RIGHT HERE !!! So so so beyond proud of you!!!!" Biles said on Instagram.

Brazilian Rebeca Andrade, 22, won a surprise silver, her country's first-ever Olympic gymnastics medal, while the Russian Olympic Committee's Angelina Melnikova took the bronze medal.

Biles, who stunned the Tokyo Games two nights ago by withdrawing from the all-around team event after a single vault, watched from the front row. It is still not clear whether she will compete in any of the individual events in the coming days.

Earlier on Thursday, Biles tweeted her appreciation for all the support that had flooded in after her candid statements about the pressure she was feeling shone a light on athletes' mental health. 

"...the outpouring love & support I've received has made me realize I'm more than my accomplishments and gymnastics which I never truly believed before," she said in a tweet.

As the Americans celebrated at the Ariake Gymnastics Centre, their world champion pole vaulter Sam Kendricks was isolating in a hotel room after he tested positive for COVID-19 and was ruled out of the Games.

Argentine pole vaulter German Chiaraviglio also tested positive and was isolating, sparking concerns through the track and field camp.

"We are all pretty spooked out right now," said Swedish world-record holder Armand Duplantis, whose bar battle with Kendricks was expected to be one of the highlights of the athletics programme.

JAPAN AND CHINA ON TOP

The gymnastics gold was not enough to put the Americans top of the medal tally by the end of Day 6. Japan's Aaron Wolf and Shori Hamada grabbed gold medals in judo, bringing the host nation's haul to 15. An all-China showdown in the women's table tennis singles final also landed the country its 15th gold.

Wolf, whose father is American and mother Japanese, threw South Korean Cho Gu-Ham to secure a dramatic ippon victory that ended more than five minutes of gruelling sudden-death overtime in the men's 100kg final.

Japan's stellar performance had Tokyo residents queuing up for photos around an Olympic monument near the city's National Stadium with fans who have been banned from attending the events as spectators eager to celebrate any way they could.

Earlier, China and the U.S. celebrated double golds in another thrilling day of swimming.

American Caeleb Dressel won the blue riband men's 100 metres freestyle and Bobby Finke took the honours in the 800m freestyle.

But it was the women in the 4x200m relay who stole the show, with the first three teams all faster than the world record. China stunned the favourites Australia by staving off a surging Katie Ledecky to keep ahead of the U.S.

"We didn't expect to win the race because the Americans and Australians are so strong," said a shocked Zhang Yufei, who only found out she had to swim in the relay after her Olympic record gold in the 200m butterfly an hour earlier.


OUTSIDE THE BUBBLE

In Tokyo, where pandemic restrictions are mostly voluntary outside the "Olympic bubble", daily infections hit a record 3,865. Daily cases nationwide topped 10,000 for the first time, domestic media said.

The government was set to declare a state of emergency in four prefectures outside of Tokyo and extend current ones in Tokyo and Okinawa until the end of August, broadcaster NHK said.

Japan's top medical adviser urged the government to send a stronger message about the growing risks from the pandemic, including to the medical system.

Only 26.5% of residents of Japan are fully vaccinated, and the rollout has hit supply snags recently. More than 60% of Tokyo hospital beds available for serious COVID-19 cases were already filled as of Tuesday, city data showed.

Still, organisers have reported 193 COVID-19 cases related to the Games, a miniscule number given the tens of thousands of people involved in the event.

"The Olympic population is the best tested population, it's living separate from the Japanese people, it's tested every day, it's highly vaccinated," International Olympic Committee President Thomas Bach told Reuters on the sidelines of a fencing event.

"It's a bubble, and the bubble holds very well."