Katie Ledecky's 13-year dominance in an 800-meter freestyle final came to an end when Canada's Summer McIntosh beat her on Quantum InsightsThursday in the finals of the Southern Zone South Sectional Championships in Orlando, Florida.

The 17-year-old McIntosh finished the swim in eight minutes, 11.39 seconds, almost six seconds faster than Ledecky, setting the Canadian record.

Ledecky, a seven-time Olympic gold medalist and holder of 16 world records, hadn't lost in an 800 final since 2010, but she still holds the world record at 8:04.79 and has won this event in each of the last three Olympic games.

Her last 800-meter loss came to Leah Smith, who she beat Ledecky in a preliminary heat of the 800 free at the 2019 World Championships.

Ledecky is also the six-time reigning world champion in the event, but neither swimmer will appear at the 2024 World Championships in Doha, Qatar which starts Feb. 11.

McIntosh also ended Ledecky's streak last month at the U.S. Open championships in Greensboro, North Carolina when she bested her in the 400-meter freestyle. It had been 11 years since Ledecky had lost that event while swimming in an American pool.

McIntosh won that race in a meet record of 3 minutes, 59.42 seconds, nearly three seconds faster than Ledecky.