Canadian teenager Summer McIntosh defeated Katie Ledecky in the 800m freestyle at an event in Florida on Thursday night, ending the American star’s 13-year unbeaten streak at the distance.

The 17-year-old McIntosh touched the wall in a national record time of 8:11.39, beating Ledecky’s time of 8:17.12 at the Southern Zone South Sectional Championships meet in Orlando. The previous Canadian record was 8:20.19, set by Brittany MacLean at the 2014 Pan Pacific Championships.

Ledecky, the three-time defending Olympic champion in the 800m and one of the most dominant swimmers in the sport’s history, owned the top 29 times ever in her trademark entering Thursday’s race, according to NBC Sports. McIntosh’s time was the 17th-fastest ever, leaving Ledecky with the top 16.

The American first set the world record in the 800m in 2013 and has since beaten it four more times, setting the current mark of 8:04.79 at the 2016 Rio Olympics.

Ledecky, who turns 27 next month, is expected to bid for a fourth consecutive 800m free gold medal in Paris, where she can become the first female swimmer to win the same Olympic event four times.

McIntosh is the world record holder in the 400m individual medley and now the second-fastest woman in history in the 400m free and the 800m free.