DOHA, Qatar -- Canadian wunderkind Summer McIntosh has ended Katie Ledecky's 13-year unbeaten streak in the 800-meter freestyle in a major upset in the lead-up to the Paris Olympics.
McIntosh clocked 8 minutes, 11.39 seconds at a sectionals meeting in Orlando, Florida, on Thursday to finish nearly six seconds faster than Ledecky.
Ledecky suffered her first defeat in the 800 since 2010, while 17-year-old McIntosh's swim made her the second-fastest woman in the distance behind the American world-record holder.
Ledecky still owns the 16 fastest times in history, including her 8:04.79 world record.
The 26-year-old has dominated the 800 like no other, winning successive gold medals at the London, Rio and Tokyo Olympics. She is expected to defend her 800 gold in Paris and bid to become the first woman to win four successive titles in Olympic swimming.
She won her sixth consecutive world title in the 800 at last year's championships in Fukuoka, Japan.
McIntosh has rapidly established herself as one of the world's top swimmers, winning back-to-back world titles in the 200-meter butterfly and 400-meter medley.
She has focused on middle-distance events since missing the 800 final in Tokyo as a 14-year-old, but the result in Florida might encourage her to return the 800 to her Olympic program.
Both McIntosh and Ledecky have elected to skip the world championships, which start in Doha on Sunday, but Ledecky's upset was a hot topic among the entrants in Qatar.
"I have some friends of the Canadian team, and I know Summer pretty well," said American Hunter Armstrong, who will defend his 50-meter backstroke world title in Doha. "I'll have to shoot her a text and congratulate her."