American swimmer Michael Phelps, the most decorated Olympian of all time, won his 21st medal Friday at the London Games, as the United States ruled the pool and excitement built toward a weekend of fierce track and field competition.
Phelps closed his individual career by claiming the gold in the 100-meter butterfly, while 17-year-old Missy Franklin grabbed her third gold medal of the Games in the 200-meter backstroke.
Meanwhile, Briton Jessica Ennis thrilled a raucous home crowd with a world-best time for a heptathlete in the 100-meter hurdles. Lithuania's Austra Skujyte, however, set an Olympic record in the shot put to take the overall lead in the seven-event competition.
Ethiopia's seven-time world champion Tirunesh Dibaba destroyed the field in the women's 10,000-meters, finishing nearly six seconds ahead of Kenyan Sally Kipyego and a full 10 seconds ahead of the reigning world champion, Kenyan Vivian Cheruiyot.
South Korean Oh Jin-hyek won his country's first individual archery gold medal.
Jamaican sprinter Usain Bolt defends his 100-meter title Sunday, and his 200-meter crown four days later.
Audiences the world over witnessed history Friday, watching as several countries fielded female athletes for the first time. Saudi Arabia's Wojdan Ali Seraj Abdulrahim Shahrkhani was greeted with applause when she took to the mat in the women's judo competition, becoming the first Saudi woman ever to compete in the games.
Noor Hussain al-Malki made history as the first woman to represent Qatar in athletics, competing in the women's 100-meter sprint. She appeared to injure her leg and did not finish.
Afghanistan's only female athlete - Tahmina Kohistani - also ran in the 100 meters, finishing last, but running a personal best of 14.42 seconds. Iraq's Dana Abdul Razak placed second in her women's 100-meter heat, advancing to the next round.