The American swimmer Aaron Peirsol broke his world record in the men's 100m backstroke in a time of 52.54 seconds, winning back to back titles.
His compatriot Matt Grevers collected the silver as the US team continued to dominate in the pool.
Australia's Hayden Stoeckel shared the bronze, touching the wall in 53.18 seconds to finish equal third with Russian Arkady Vyatchanin.
