Kosovo's Majlinda Kelmendi made Olympic history for her home nation, winning a gold medal in women's judo.
In doing so, she has become the first athlete from the Balkan nation to win an Olympic medal.
The Rio games are the first in which athletes from Kosovo have been allowed to compete under their own flag.
Kelmendi defeated Italy's Odette Giuffrida by yuko-- a type of body throw-- in the final of the women's 52-kilogram category.
WATCH: Kosovo's First Olympic Team Ready For Rio
For neighboring Serbia, it was a day of disappointment in Rio, as the world ranked No. 1 men’s tennis player, Novak Djokovic lost his first-round match to Argentina’s Juan Martin del Potro. Del Potro is ranked No. 145.
U.S. swimmer Michael Phelps won his 19th Olympic gold medal and his 23rd Olympic medal overall as part of the U.S. 4x100 men’s relay team.
Also on August 7, the second day of the 2016 games, Swedish swimmer Sarah Sjostrom broke her own world record in the 100-meter butterfly, taking the gold with a time of 55.48 seconds. And U.S. swimmer Katie Ledecky broke her own world record in the women’s 400-meter freestyle with a time of 3:56.46.
Britain’s Adam Peaty broke his own world record for the second time in two days to win gold in the 100-meter men’s breaststroke. He became the first British male swimmer to win Olympic gold in 28 years.
Chinese weightlifter Long Quinquan set a world record with a combined total of 307 kilograms to take the gold in the men’s 56-kilogram category. He broke a 16-year-old record of 305 kilograms set by Turkey’s Halil Mutlu in Sidney in 2000.
Chinese diver Wu Minxia also entered the record books by becoming the most decorated diver in history. Wu became the first person ever to win five Olympic diving gold medals when she won the 3-meter synchronized springboard competition with partner Shi Tingmao. Wu, 30, also became the oldest woman to ever win an Olympic diving gold medal.
Earlier, Russia’s Vitalina Batsarashkina won silver in the women's 10-meter air pistol event, beaten out by Zhang Mengxue who secured China's first gold for this year's games.
U.S. tennis stars Serena and Venus Williams lost their bid to defend their Olympic women’s doubles title by losing to the Czech pair Lucie Safarova and Barbora Strycova in the first round. The Williams sisters won Olympic doubles gold in 2000, 2008, and 2012. Serena Williams is the defending women’s singles Olympic champion, while Venus Williams won that title in 2000.
The U.S. women’s basketball team routed Senegal 121-56 to extend its Olympic winning streak to 42 games. The team has taken the gold without being beaten in seven of the last eight Olympic games.
In women's road cycling, Anna van der Breggen delivered the Netherlands its first gold medal of the Rio games in a tense finish that saw her teammate Annemiek van Vleuten injured in a violent fall. She suffered a severe concussion and three lumbar spinal fractures.
In other sports, the Russian women’s archery team won the silver medal. Ksenia Perova, Tuiana Dashidorzhiyeva, and Inna Stepanova lost to South Korea 5-1. Taiwan took the bronze.
It was South Korea’s eight consecutive gold medal in the event.
In fencing, Russia’s Timur Safin took the gold medal in the men’s foil competition, defeating the United Kingdom’s Richard Kruse. Safin, who was born in Tashkent, Uzbekistan, has competed for Russia since 2012.
Meanwhile, high winds forced organizers to call off competition in the rowing regatta for a second day.
That decision was welcomed by teams who had seen three boats capsize as waves washed over them.
Officials at the games said that a bullet the came through the roof of the media tent at the Equestrian Center on August 6 probably came from a nearby slum. Police believe a gang member may have fired the shot at a police drone or blimp.
The International Olympic Committee (IOC) on August 7 said a total of 278 Russian athletes have so far been cleared to participate in the Rio games, following allegations of massive, state-organized doping against Russia. Moscow had planned to send 389 athletes to the games.
Several cases are still pending and additional athletes may yet be cleared to compete.
A total of 14 gold medals were up for grabs in the second day of competition.
The Rio games will continue until August 21.
With reporting by Reuters, AP, Interfax