Allyson Felix won her first round 400m heat in 51.24 seconds to advance to the semifinals. Comfortably in the lead, she slowed to a jog over the final 50m before accelerating as she crossed the finish line.
Felix, the 2015 400m world champion, is running the individual 400m for the first time at the Olympics. But she does have two Olympic 4x400m gold medals.
Fellow Americans Phyllis Francis and Natasha Hastings also advanced to the 400m semifinals. All three U.S. athletes won their heats.
Francis, who clocked 50.58 seconds, had the fastest time in the eight heats.
The women’s 400m semifinals will take place Sunday at 7:35 p.m. ET, followed by the final Monday at 9:45 p.m. ET.
While in Rio, Felix had the opportunity to meet U.S. Secretary of State John Kerry.