Dalilah Muhammad burst out of the starting blocks and never looked back. The U.S. athlete dominated the 400m hurdles, racing to a clear win in 53.13 as the U.S. finished 1-3 to lay claim once again as the best hurdling country in the world.

Ashley Spencer of the U.S. finished third in 53.72 as Sara Peterson of Denmark won the silver medal in 53.55.

Muhammad's gold was the first gold medal for the U.S. in the event.

The U.S. women are doing work in the hurdle events. They became the first country to sweep the top three spots in the women's 100 meter hurdles when Brianna Rollins, Nia Ali and Kristi Castlin finished 1-2-3 on Wednesday, and they're even having success in the distances. Emma Coburn won bronze in the 3,000-meter steeplechase on Monday.

After not winning a gold medal on the track until Wednesday -- they had won gold in the field events -- the U.S. is cleaning up. After the medal sweep in the women's 100 hurdles last night, Kerron Clement won the 400 hurdles for the men on Thursday morning. Team USA is cleaning up, mostly thanks to the hurdles.