In a stunning upset at the U.S. Open Championships in Greensboro, North Carolina, Katie Ledecky faced her first loss in an American pool in the 400-meter freestyle race in 11 years. The title was claimed by Canadian teenager Summer McIntosh, who outpaced Ledecky by nearly three seconds.

McIntosh completed the race with a remarkable time of 3 minutes, 59.42 seconds, setting a new meet record, as reported by the Associated Press. Ledecky, a seasoned champion, followed with a time of 4:02.38. It was Ledecky's first loss in her home country in this event since the 2012 U.S. Olympic trials, where she finished third at just 15 years old.

This isn't the first time McIntosh has challenged Ledecky's dominance. Last March, the 17-year-old ended Ledecky’s nine-year winning streak in the U.S. in the 200-meter freestyle. Despite this, the full impact of McIntosh's victory is challenging to assess, given that swimmers are currently in various stages of training, gearing up for the Paris Olympics next year.

McIntosh briefly held the world record in the 400 free before Australia’s Ariarne Titmus reclaimed it with a time of 3:55.38 at the world championships in Fukuoka, Japan. In that event, Ledecky secured a runner-up position, while McIntosh finished fourth. Titmus is the reigning Olympic champion in the 400 free, a title Ledecky won at the 2016 Rio de Janeiro Games.

Ledecky's defeat signals a shifting landscape in women's swimming, with young talents like McIntosh rising to challenge established champions. As preparations for the Paris Olympics intensify, the swimming world watches keenly to see how these rivalries and talents evolve on the global stage.