Ledecky, trailing McIntosh at the 700-meter mark, surged ahead on the final lap, fending off a hard-charging Pallister as McIntosh faded in the closing meters. With the win, Ledecky remained undefeated in the 800-meter freestyle finals event on the world stage dating back to 2012.

American great Katie Ledecky beat Summer McIntosh to win a thrilling 800m freestyle title on Saturday and said her rule for the event is simple -- "I don't lose 800s". I kind of have this fake rule -- I don't lose 800s.

Katie Ledecky won the 22nd world title of her legendary career to close in on Michael Phelps's record as fellow Olympic champions David Popovici and