Katie Ledecky and teammate Shannon Vreeland rest after the 200-meter freestyle final at the Pan Pac swimming championships in Gold Coast, Australia. Ledecky took gold and Vreeland bronze. (Patrick Hamilton/AFP/Getty Images)

When Katie Ledecky qualified for the London Olympics in 2012, she was a newcomer to the international swimming scene, too inexperienced to be predictable and too naive to be overwhelmed.

Two years later, at age 17, she is the most consistent performer on the U.S. national team.

With an ailing Missy Franklin battling back spasms and a lackluster performance from her teammates during the prelims, Ledecky, a rising senior at Stone Ridge School of the Sacred Heart in Bethesda, sparked the U.S. team Thursday with two gold medals on the first night of the Pan Pacific Championships in Gold Coast, Australia.

The typically modest Ledecky shrugged off the stunning performance that wowed the near-sellout crowd at the Gold Coast Aquatic Centre’s newly constructed outdoor competition pool. She won the 200-meter freestyle then nearly broke her own world record in the 800 freestyle.

It was her first international victory in the 200 and her third straight in the 800.

Ledecky finished the 800 in 8 minutes 11.35 seconds, just shy of her world record swim in June when she set the mark in the event for the second time in her career. For a few brief moments, it appeared Ledecky would break the mark for a third time on a third continent.

“I wasn’t really focusing on hitting a certain time, I just wanted to get through the double and see if I could handle both races,” Ledecky said. “It was my first big international double — I’m really happy how I handled it.”

Ledecky, who entered the meet as the world record-holder in the 400, 800 and 1,500 freestyle, began challenging her record-setting pace in the 800 after just two laps. When she flipped at the 600-meter turn, Ledecky was a body length ahead of the pace but faded in the final lengths. Still, she broke Janet Evans’ Pan Pacs record of 8:16.22 set in 1989.

“I don’t think it’s ever normal,” said Ledecky when asked whether her record-setting swims have become commonplace. “It’s nice to get close to it, and I think I can certainly improve on what I’ve done this year.”

Ledecky won the 200 free in 1:55.74, also a meet record, ahead of Australia’s Bronte Barratt and U.S. teammate Shannon Vreeland.

Franklin, whose status was in doubt ahead of Thursday morning’s prelims, won the “B” final in the second-fastest time of the night to earn a spot at next year’s world championships in Kazan, Russia, alongside Ledecky.

Thirty minutes later, Franklin returned to the pool for the women’s 100 backstroke ‘A’ final. The reigning Olympic and world champion finished third behind Australia’s Emily Seebohm and Belinda Hocking. Seebohm won in a world-best 58.84.

“I’m really proud of myself. It has nothing to do with my times, my places,” said Franklin, who set a world championships record with six gold medals last year. “Just getting out and kind of fighting back against life right now.”

Seebohm told reporters she was happy to earn gold regardless of the circumstances.

“A win is a win,” said the Olympic silver medalist. “She is obviously a strong competitor and, sometimes, you just have to go out and race your competition. It gives me a lot of confidence going forward.”

Ledecky led a first-day barrage of medals for the U.S. team, which won 10, including four gold.

Cammile Adams led a gold-bronze U.S. finish in the women’s 200 butterfly. Katie McLaughlin, 17, took bronze to qualify for a berth on the world championship team — her first. Connor Jaeger won the men’s 1,500 freestyle in 14:51.79, edging Canada’s Ryan Cochrane by .18 seconds . Australia’s 18-year-old freestyle phenom Mack Horton won bronze.

Olympic and world champion Matt Grevers finished second in the men’s 100 backstroke to Japan’s Ryosuke Irie. Tyler Clary picked up a bronze in the men’s 200 butterfly behind Daiya Seto of Japan and Leonardo De Deus of Brazil.

Michael Phelps, the 18-time Olympic gold medalist competing in his first international championship since ending his retirement in April, is scheduled to swim the 100 freestyle on Friday.