Katie Ledecky suffered her first loss in a major international 400m freestyle, getting run down by Australian 18-year-old Ariarne Titmus in the last 50 meters to open the world championships in Gwangju, South Korea on Sunday.
Titmus overcame a .62 of a second deficit going into the last 50 and won by 1.21 seconds over Ledecky in 3:58.76. Ledecky held off countrywoman Leah Smith by 1.32 seconds for the silver.
Ledecky had won the last six major international 400m frees among the world championships, Pan Pacific Championships and Olympics dating to 2013.