Dalilah Muhammad, of the United States prepares to race in the women's 400 meter hurdles semifinal at the World Athletics Championships in Doha, Qatar. Photo: AP Photo/Petr David Josek

DOHA - American Dalilah Muhammad broke her own world record in the 400-meter hurdles Friday night, circling in 52.16 seconds to top the mark she set earlier this year by .04 seconds.

The late-blooming 29-year-old, who didn't have a sponsor or a spot at the London Olympics seven years ago, took a smooth-as-silk path around the track to re-write a mark that had gone 15 years without being touched before she did it at U.S. nationals in July.

She needed every fraction, as her lean into the line was only good enough for a .07-margin over 20-year-old Sydney McLaughlin, whose time of 52.23 would've been the world record 10 weeks ago. But not good enough now.

Dalilah Muhammad, left, of the United States, finishes ahead of Sydney Mclaughlin, right, of the United States, to win the the women's 400 meter hurdles final. Photo: AP Photo/David J. Phillip

While the rest of the women sprawled onto the track after completing the grueling lap, Muhammad had other business to take care of — namely, having her picture taken by the clock displaying her new mark.

Muhammad, who is from New York City and went to college at the University of Southern California, won the gold medal at the Rio Olympics and has silvers from the 2013 and 2017 world championships.

It was the first individual world record set on the track this week in Doha, where the elements in the air-conditioned stadium couldn't be much different from the last time she set the mark. That time, in Des Moines, Iowa, she won it in the rain, with puddles forming on the track.

Dalilah Muhammad of the United States wins the gold medal in the women's 400 meter hurdles at the World Athletics Championships in Doha. Photo: AP Photo/Petr David Josek

AP