Anna Cockrell claimed the third qualifying spot in 53.70sec.

EUGENE, United States (AFP) - Sydney McLaughlin set a world record in the women s 400m hurdles at the US Olympic trials on Sunday, clocking 51.90sec after a thrilling battle with rival Dalilah Muhammad.

The 21-year-old star became the first woman ever to duck below the 52-second barrier after running a superb tactical race against reigning Olympic and world champion Muhammad.

Muhammad, who had held the previous world record of 52.16sec following her win over McLaughlin at the 2019 World Championships in Doha, was second in 52.42sec.

Anna Cockrell claimed the third qualifying spot in 53.70sec.