A major upset in women's tennis leads the highlights of day-four photos at the Rio Games.
Elina Svitolina of Ukraine in action as she beat four-time Olympic champion Serena Williams of the United States.
China's Jiao Yunlong (L) competes against Ukraine's Bogdan Nikishin during their men’s individual epee qualifying bout as part of the fencing competition.
Katinka Hosszu of Hungary on her way to winning the women's 200-meter individual medley gold medal.
U.S. swimmer Michael Phelps (L) with his fiancee Nicole Johnson (R) and their son Boomer (C) after he received the gold medal in the men's 200-meter butterfly competition.
Jessica Phoenix of Canada rides a horse called A Little Romance to victory in the eventing competition.
An unidentified French rider and horse sail over a jump during the eventing finals.
Izzat Artykov of Kyrgyzstan competes in the men's 69-kilogram weightlifting final in which he won a bronze medal.
Karina Goricheva of Kazakhstan makes an attempt during the women's 63-kilogram weightlifting event.
U.S. gymnast Gabrielle Douglas competes on the uneven bars, as the United States won the gold medal in the women's team final.
U.S. gymnast Simone Biles (C) celebrates with teammates following her floor routine in the women's team final.
A member of Brazil's national security forces looks on during the rowing competition.
Chinese players jump during a women's water polo match against Hungary.
Supporters hold Brazilian flags during their country's volleyball game against Canada.
Zahra Nemati of Iran, a disabled archer who was Iran's flag-bearer for the Rio games, loses her match against Inna Stepanova of Russia.
Khasan Khalmurzaev of Russia (L) in action as he defeats Travis Stevens of the United States (R) to win the men's 81-kilogram judo gold medal.
A tattoo of the Olympic rings is seen on the leg of Turkey's Busra Katipoglu during the women's 63-kilogram judo event.
Competitors in the men's single sculls rowing quarterfinal.