Beijing - American Aaron Peirsol on Tuesday broke the 10th swimming world record at the Beijing Olympics as he won the men's 100m backstroke in a time of 52.54 seconds. The silver medal went to compatriot Matt Grevers with 53.11, while Russian Arkady Vyatchanin and Australian Hayden Stoeckel shared the bronze 0.07 seconds behind Grevers.
Peirsol's time beat the 52.89 he swam at the US trials in July. It was the 10th world record in Beijing Olympic swimming.
Earlier Tuesday Michael Phelps joined the list of most successful Olympian athletes in the history of the games as he broke the world record in the men's 200m freestyle to win his third gold medal of these games and his ninth gold medal overall.
The American swimming superstar won the event with a time of 1:42.96, beating South Korean Park Tae Hwan (1:44.85) and American Peter Vanderkaay (1:45.14) into second place.
