BEIJING — Aaron Peirsol has won the men's Olympic 100-meter backstroke, defending his title with a world-record time and extending the United States' dominance of the event.

Peirsol touched in 52.54 seconds, lowering his old mark of 52.89 set at last month's U.S. trials.

Teammate Matt Grevers earned the silver in 53.11. Arkady Vyatchanin of Russia and Hayden Stoeckel of Australia tied for the bronze in 53.18.

The U.S. has won the men's 100 back at four consecutive Olympics, with Peirsol taking the title in Athens in a time that was 0.17 second slower.