Key moments from the Olympic Games: Day 6

Here's what you missed from Day 6 of the 2020 Summer Olympics in Tokyo.

Sunisa Lee wins gold

Sunisa Lee won the gold medal after a tremendous performance in the individual all-around competition. Lee’s teammate Simone Biles cheered her on from the stands as Lee delivered a strong floor exercise routine to seal the win.

Biles withdrew from the competition Wednesday so she could "focus on her mental health," USA Gymnastics said in a statement Wednesday. Biles' replacement in the competition, Jade Carey, finished in 8th place.

Caeleb Dressel wins gold in 100m freestyle, sets Olympic record

U.S. swimmer Caeleb Dressel won his first individual gold medal after a record-setting time of 47.02 seconds in the 100m freestyle. Fellow swimmer Robert Finke took home the gold in the 800m freestyle event, increasing Team USA's gold medal count to 13.

COVID-19 cases at Tokyo Olympics rise to 198, Tokyo sees record number of cases

There were 24 newly confirmed cases of COVID-19 among people at the Tokyo Olympics on Thursday, including U.S. pole vaulter Sam Kendricks and two other athletes staying in the Olympic village. The total now stands at 198, according to data released by the Tokyo 2020 organizing committee.

The surrounding city of Tokyo reported a record high of 3,865 new cases on Thursday, a seven-day average increase of 161.9%, according to data released by the Tokyo metropolitan government.

Heat continues to be a factor, tennis matches moved to later afternoon

The heat index hit 99 degrees on Wednesday, causing athletes, including the world's second-ranked tennis player, Daniil Medvedev, to seek medical attention. The matches were moved from 11 a.m. to 3 p.m. local time to avoid the hottest part of the day, the International Tennis Federation announced in a statement.

Djokovic 2 matches away from Golden Slam

Serbia’s Novak Djokovic, the top ranked tennis player in the world, is two matches away from achieving a Golden Slam after defeating Japan’s Kei Nishikori 6-2, 6-0. A player would have to win all four major events and the Olympics in a calendar year, a triumph only ever attained by Germany's Steffi Graf.

20 athletes banned from Olympics before Friday's track and field opening

Athletes from Belarus, Bahrain, Ethiopia, Kenya, Morocco and Nigeria were barred from competing after they did not meet the anti-doping requirements by the Athletics Integrity Unit, according to The Associated Press. The athletes were part of the track and field competitions, which begin Friday.

More scenes from today's action:

Catch up on the best moments from the previous days' events

For more Olympics coverage, see: https://abcnews.go.com/Sports/Olympics