Last week Medvedev was the first to appeal for a delayed start for tennis at the Tokyo Olympics due to the hot and humid weather conditions and also received support from world number one Novak Djokovic.

The superstar American gymnast Biles on Tuesday stunned the Tokyo Olympics when she pulled out of the women's team final, saying: "I have to do what's right for me and focus on my mental health and not jeopardise my health and my wellbeing."

Biles sent a shock through the Summer Games on Tuesday when she dropped out of the team competition on her opening vault after receiving a low mark.

Osaka, who lit the Olympic cauldron and was one of the faces of the Games, struggled in an error-strewn display that blew the draw wide open after the earlier exits of world number one Ashleigh Barty and third seed Aryna Sabalenka.

The world number two was swiped aside 6-1 6-4 by Czech Marketa Vondrousova in an early shock on Day Four of the Games.

The two athletes, one of whom is a Dutch tennis player, were both living in the athletes' village, according to the organizers. The others are three games-related officials, one contractor and a member of the organizing committee.

Osaka, the star of the opening ceremony, defeated China's Zheng Saisai 6-1, 6-4 and said she felt "refreshed" after taking an eight-week break for mental health reasons.

The action began early at Tsurigasaki Surfing Beach, about 100 kilometres (60 miles) east of Tokyo, with the first surfers paddling out in favourable wave conditions.

Indonesia's Jonatan Christie was competing at a tournament in Thailand earlier this year when he learned that his older brother, Ivan, had contracted the illness back home.

Bach's speech, which drew on familiar themes of peace, solidarity and gratitude for overcoming the coronavirus hardships, immediately drew ire on Twitter and in traditional Japanese media.

The team of Cate Campbell, Emma McKeon, Meg Harris and Bronte Campbell lowered the 3:30.05 Australia set at the 2018 Commonwealth Games to reinforce their dominance of the event.

Murray, 34, will stay in Tokyo to play doubles with Joe Salisbury. The pair won their opening match of the competition on Saturday. 

Barty, the reigning Wimbledon champion, dropped serve twice in each set as 48th-ranked Sorribes Tormo made just five unforced errors to the Australian's 27 to earn a shock win.

Teenager Windy Cantika Aisah took the bronze for Indonesia after smashing her personal best twice in the clean and jerk.

Here's what you need to know about the Tokyo Games:

Japanese tennis star Naomi Osaka lit the Olympic cauldron in Friday's opening ceremony at an eerily empty stadium after the coronavirus forced organisers to ban spectators at all but a handful of venues.

The Olympics have faced opposition in Japan over fears the global gathering of 11,000 athletes could trigger a super-spreader event, and is taking place under strict virus measures.

The ceremony raised the curtain on the biggest sporting spectacle held since the virus took hold early last year and following a one-year postponement. Involving about 11,000 athletes from over 200 countries and regions, venues will be without spectators for the first Olympics in history.

Those Games were enthusiastically embraced in Japan and abroad, and heralded a new era for the nation after it emerged from the devastation of World War II and was on its way to becoming an economic powerhouse.

Only a few hundred dignitaries and officials will be allowed into the 68,000-capacity venue to watch the opening extravaganza of the Games that were postponed last year because of the pandemic, but crowds of residents from Tokyo and beyond flocked to the venue looking to soak up the atmosphere.

Both have already achieved enough to be considered the greatest gymnasts of all time, but they approach the delayed 2020 Games as hungry as ever to enhance reputations that already stand as tall as nearby Mount Fuji.

The identity of the final torchbearer is one of the Games' most closely held secrets yet speculation has swirled for months around well-known athletes including Naomi Osaka, the four time Grand Slam tennis champion, whose superstar status could also draw attention away from the string of gaffes in the build-up to the Games and soften public resentment over the hosting of the Games during the pandemic.

Committee chief Raja Sapta Oktohari said, "We will not back down and will continue to fight for the 2036 Olympics," promising more solid preparation.

The opening ceremony at the National Stadium will raise the curtain on the biggest sporting spectacle held since the virus took hold early last year. Involving about 11,000 athletes from over 200 countries and regions, venues will be without spectators for the first Olympics in history.

Coates, also the head of the Australian Olympic Committee, publicly berated Queensland Premier Annastacia Palaszczuk over her plans not to attend the event, after her state capital Brisbane was named 2032 host city late Wednesday.

And with just days until the opening ceremony, the Japanese leader said Tokyo was "in the right place, and we're ready to go."

Queensland state Premier Annastacia Palaszczuk and the Australian delegation will provide a final presentation to IOC members in Tokyo before the vote at around 5:10 p.m. (0810 GMT)