Summer McIntosh smashed the decade-old world record in the women's 200m individual medley on Monday, touching the wall in 2 minutes 05.70 seconds for her second record at the Canadian swimming trials.
The 18-year-old eclipsed Hungarian Katinka Hosszu's mark of 2:06.12 set at the 2015 World Championships to become the first woman to duck under 2:06.
It was triple Olympic gold medallist McIntosh's second world record of the meet following her 400m freestyle world record on Saturday.
The gifted Canadian teenager had also impressed during Sunday's victory in the 800m freestyle, clocking the third-fastest time in history in an event not typically regarded as her strongest.
Yet McIntosh showed no signs of fatigue with another dazzling performance to delight the crowd in British Columbia on Monday.
"Overall really happy with that time and always just trying to keep pushing forward," McIntosh said after her record-breaking display.
"It's awesome. 200IM is my main race out of my top five or six races where I really have to execute perfectly.
"There's no room for mistakes and it's kind of a sprint event for me, so I'm really happy with that. It gives me a lot of confidence heading into Singapore," added McIntosh, referring to next month's World Championships.
Asked how she had prepared herself for Monday's effort after a gruelling weekend, she added: "Just recovering, sleeping as much as possible and eating a lot.
"And also mentally calming myself down and taking it one race at a time.
"I've had a lot of practice at that these past few years."
McIntosh laid the foundations for her assault on the record with flawless opening sections in the butterfly and backstroke before an improved breaststroke – her weakest discipline – left her on world record pace.
From there she turned on the after-burners in the closing freestyle to obliterate Hosszu's record.
Mary-Sophie Harvey trailed in second in 2:08.78 with Ashley McMillan third in 2:12.08