On 3 October 2019, Naser became the 400 metres World Champion at the Doha World Championships, the youngest ever, and also first Asian woman winner of that title in the event. She improved her personal best, set one year earlier, by a massive 0.94 s, and her result of 48.14 seconds has been the fastest since 1985 – that is for 34 years (when Marita Koch set a world record of 47.60), the second fastest at a World Championships (only behind Jarmila Kratochvílová who ran 47.99 in 1983), and the third fastest of all time. This had been her fifth race in five days, and top five women all set PBs. She additionally won a bronze medal for the 4×400 m mixed relay, which set an Asian record. During 2019 Military World Games, the sprinter finished as a gold medalist in her signature event extending her unbeaten streak in the event to 14 straight finals, and a bronze one in the 4×100 m relay. Naser finished the 2019 season unbeaten.