Katie Ledecky enhanced her status as swimming's new teen queen with two victories in less than an hour on the opening day of the Pan Pacific championships on Thursday.
The 17-year-old American took the 200 metres freestyle after world champion Missy Franklin failed to qualify for the final. She then left her rivals in her wake to win the 800m freestyle, coming within a whisker of breaking the world record she set less than two months ago.
Franklin, who has been troubled by back spasms and almost missed the meet, won the 200m consolation final in a time that would have got her second place in the A final before finishing third behind Australia's Emily Seebohm in the 100m backstroke.
Ledecky was named World Swimmer of the Year in 2013 after breaking the world record for 800m and 1500m, but is turning her attention to shorter distances.
She broke the 400m world record this month and is swimming the 200m at an international meet for the first time.
Her winning time of Thursday was one minute 55.74 seconds, almost a second and a half clear of her nearest rival. She clocked 8:11.35 in the 800m, just 0.35 outside her world record.
“I wasn’t really focusing on hitting a certain time," she told reporters at Australia's Gold Coast. "I just wanted to get through the double and see if I could handle both races.
"It was my first big international double. I’m really happy how I handled it.”
Franklin won six gold medals at last year's championships in Barcelona but was well off her best on Thursday. "There is still some discomfort but it is getting much, much better day by day," the 19-year-old told reporters after the heats.
Seebohm was impressive in winning the 100m backstroke, stopping the clock at 58.84 seconds, and she was delighted to finally beat her nemesis Franklin.
"A win is a win," Seebohm told reporters. "Sometimes you don't feel fantastic and you have to go out and do your best.
"She is obviously a strong competitor and, sometimes, you just have to go out and race your competition."
The United States won four of the eight finals contested on the opening night of the four-day meet with Camille Adams (women's 200m butterfly) and Conor Jaeger (men's 1500m freestyle) joining Ledecky on top of the podium.
Thomas Fraser-Holmes won the men's 200m freestyle to give the host nation a second gold. Japan won the other two races, with Ryosuke Irie upsetting Olympic champion Matt Grevers in the men's 100m backstroke and Daiya Seto taking the women's 200m butterfly.
Michael Phelps, competing in his first international meet since retiring after London 2012, is scheduled to make his first appearance on Friday.
(Reporting by Julian Linden in Singapore; Editing by Robert Woodward)