IRVINE, United States, Aug 10, 2014 (AFP) -Katie Ledecky swam a "pretty close to perfect" race on Saturday to seize the 400m freestyle world record at the US Championships.
The 17-year-old schoolgirl powered to victory in a dazzling 3min 58.86sec, eclipsing the prior world mark of 3:59.15 set by Italy's Federica Pellegrini in 2009 in the era of now-banned high-tech bodysuits.
It was Ledecky's third triumph in three races at these championships and added the 400m world record to her 800m and 1,500m free world marks to make her the first woman since Janet Evans to hold all three at the same time.
"Just pure excitement," fueled Ledecky's cap-tossing, water-pounding celebration when she looked up and saw her time.
"It never gets old to break world records," she said. "It's still really exciting for me."
However, Ledecky said she didn't go out with the aim of matching Evans, who held the 400m, 800m and 1 500m free world records simultaneously from 1988 to 2006.
"It was on my mind, but I didn't let it overtake me today," Ledecky said. "It's an honor to be mentioned in the same sentence as Janet."
Cierra Runge finished second in 4:04.67 and Leah Smith was third in 4:06.28.
Ledecky, who had already become the only woman to twice break four minutes in the event with her morning swim of 3:59.89, said she stuck to her strategy.
"I tried to make sure I didn't rush the first 100," she said. "Then after that I could just race the last 300.
"It was probably pretty close to perfect," she said.
Ledecky's performance -- particularly her back-to-back sub-four minute swims -- impressed 18-time Olympic gold medalist Michael Phelps.
"She just throws it on the line," he said admiringly.
Phelps himself doesn't even have perfection on his radar four months into a comeback after a near two-year layoff.
Phelps has accomplished his main goal of the week, punching his ticket to the Pan Pacific Championships with a runner-up finish in the 100m fly on Friday.
It's a big step on the comeback trail since the results of this meet and the PanPacs determine the US team for the 2015 world championships.
But a sixth-place finish in the 100m backstroke on Saturday underscored just how much work Phelps has ahead of him.
"When there are workouts, I need to be at every one," Phelps said. "Whatever I put my mind to, I know I can accomplish."
Matt Grevers won the back in 52.75sec, third-fastest time in the world this year.
Missy Franklin won the 100m backstroke in 59.38sec -- also third-fastest in the world this year.
She led a podium sweep by University of California swimmers with team-mates Rachel Bootsma and Elizabeth Pelton behind her.
Olympic relay gold medalist Jessica Hardy and Micah Lawrence shared the gold in the women's 100m breaststroke, both clocking 1:06.51.
That's the sixth-fastest time in the world this year, and third-placed finisher Breeja Larson grabbed the eight-fastest time of the season as she took bronze in 1:06.73.
Cody Miller won the men's 100m breaststroke in 59.91sec, breaking one minute for the first time in his career to come home ahead of Nicolas Fink (1:00.38) and Kevin Cordes (1:00.63).
Michael McBroom won the men's 400m free in 3:47.19, with Matt McLean second in 3:47.30 and Connor Jaeger third in 3:49.42.
Results of finals on Saturday, the fourth day of the US Swimming Championships:
1. Michael McBroom 3:47.19, 2. Matt McLean 3:47.30, 3. Connor Jaeger 3:49.42, 4. Reed Malone 3:49.67, 5. Michael Klueh 3:50.82, 6. Sean Ryan 3:51.30, 7. Ryan Feeley 3:53.82, 8. John Lewis 3:55.54
1. Cody Miller 59.91sec, 2. Nicolas Fink 1:00.38, 3. Kevin Cordes 1:00.63, 4. Brad Craig 1:00.82, 5. DJ MacDonald 1:00.83, 6. Zach Hayden 1:01.00, 7. Brendan McHugh 1:01.10, 8. BJ Johnson 1:01.84
1. Matt Grevers 52.75, 2. Ryan Murphy 53.21, 3. Nick Thoman 53.46, 4. David Plummer 53.57, 5. Jacob Pebley 53.90, 6. Michael Phelps 53.95, 7. Eugene Godsoe 54.66, 8. James Wells 55.41
1. Katie Ledecky 3:58.86, 2. Cierra Runge 4:04.67, 3. Leah Smith 4:06.28, 4. Elizabeth Beisel 4:07.46, 5. Becca Mann 4:07.92, 6. Lindsay Vrooman 4:09.38, 7. Gillian Ryan 4:11.19, 8. Sarah Henry 4:12.15
1. (tied) Jessica Hardy 1:06.51 and Micah Lawrence 1:06.51, 3. Breeja Larson 1:06.73, 4. Emma Reaney 1:06.74, 5. Katie Meili 1:07.44, 6. Lilly King 1:08.22, 7. Molly Hannis 1:08.82, 8. Andee Cottrell 1:09.10
1. Missy Franklin 59.38, 2. Rachel Bootsma 1:00.71, 3. Elizabeth Pelton 1:00.76, 4. Kathleen Baker 1:00.90, 5. Olivia Smoliga 1:01.08, 6. Clara Smiddy 1:01.37, 7. Cheyenne Coffman 1:01.57, 8. Ali Deloof 1:02.21