Ryan Murphy extends U.S. gold streak in 100 backstroke to 6

— -- The United States' winning streak in the 100-meter backstroke continued Monday as Ryan Murphy won in an Olympic-record 51.97 seconds for the Americans' sixth straight gold medal in the event.

China's Jiayu Xu finished second (52.31), while 30-year-old American David Plummer took home bronze (52.40) at the Olympic Aquatics Stadium in Barra's Olympic Park.

Plummer, a first-time Olympian at age 30, became the fourth-oldest swimmer, male or female, to medal in a Games debut and the oldest to do so since 1912.

Murphy, fourth at the turn, rallied on the return leg with Australia's Mitch Larkin setting the early pace.

Larkin couldn't hold on and finished three-hundredths of a second behind Plummer.

The Americans haven't lost the men's 100 back since the 1992 Barcelona Games.

Men's 200-meter freestyle

Sun Yang of China defied those who complained about his doping past by winning a gold.

Yang rallied from his customarily slow start to pass South Africa's Chas le Clos and hold off American Conor Dwyer, touching the wall in 1 minute, 44.65 seconds.

Le Clos, who recently announced that both of his parents are battling cancer, went out with a totally different strategy. He built a body-length lead over the entire field and tried to hang on. It nearly worked.

But Yang surged to the front, and Le Clos took silver in 1:45.20.

Dwyer claimed the bronze in 1:45.23.

ESPN Stats & Information and The Associated Press contributed to this report.