Hosszú clocked 4:30.39, beating Ye Shiwen of China and Yui Ohashi of Japan, who tried to give her a good battle through the first 200m.
In her career, this was her 9th long-course WC title, and her second triumph in Gwangju, as she had earlier won the 200m IM as well. She has swept the two IM titles for the fourth straight competition, making her the first-ever swimmer to do so.
In addition, the Iron Lady captured her fifth title in the 400m individual medley overall. As a result, she became the first woman to win five world titles in the same event.
In the same event, Zsuzsanna Jakabos came in 7th.