Meet records didn't stand a chance Sunday on the opening morning of the world swimming championships, the last hurrah for high-tech bodysuits.

Several swimmers came close to breaking world records at the Foro Italico, but one guy who didn't go fast enough was defending world and Olympic champion Park Tae-hwan, who shockingly failed to qualify for the final of the men's 400-meter freestyle.

"I'm surprised, too," Park said. "I couldn't get enough rest after the Olympics. I worked hard in 2005, 2006, 2007, 2008 with no rest. That was the problem."

Sarah Sjostrom of Sweden set a meet record in the very first event, just missing the fastest time ever in the 100 butterfly. American Ariana Kukors, Italy's Federica Pellegrini, South Africa's Roland Schoeman and Spain's Rafael Munoz also took down championships records, though the expected assault on the world records was likely to hold off until the evening semifinals and finals.

This is the last major meet for bodysuits, which were banned by FINA beginning in 2010.

Pellegrini thrilled the home crowd when she touched first in the women's 400 freestyle preliminaries, backing off a bit in the middle of the race before posting a time of 4 minutes, 1.96 seconds.

She was off the world record, her own mark of 4:00.41 from last month, but did beat the championship record set by France's Laure Manaudou at the 2007 worlds (4:02.61).

American Allison Schmitt was next (4:02.80), while Olympic champion Rebecca Adlington barely qualified for the final with the eighth-best time (4:05.70). American Chloe Sutton also advanced.

"At the start, I was pushing hard," Pellegrini said. "I wanted to test out the pool. After 200 meters, I realized how fast I was going and I slowed down. Then when the American (Schmitt) came up on me, I started pushing again to make sure I got first place and lane 4 for the finals."

"She definitely set the pace," Schmitt said. "I just tried to keep up with her."

The most-anticipated event on the opening day of swimming was a rematch between the U.S. and France in the men's 400 free relay.

At last year's Olympics, American Jason Lezak overcame a daunting deficit in the last few strokes and touched eight-hundredths of a second ahead of Alain Bernard, keeping Michael Phelps on track to break Mark Spitz's record with eight gold medals.

The Americans won't have Lezak this time _ he skipped the worlds to compete in Israel. Phelps rested up for the evening final, leaving Ricky Berens, Cullen Jones, Garrett Weber-Gale and Matt Grevers to swim in the prelims.

Sjostrom was fastest in the 100 fly with a time of 56.76, beating Libby Trickett's winning performance of 57.15 at the 2007 worlds. The Swede just missed Inge de Bruijn's world record 56.61, which seems certain to be among many marks fall over the next eight days.

Dana Vollmer of U.S. qualified second at 57.15 and Australian star Jess Schipper, wearing a new Adidas suit, was third at 57.17.

"This is the first time I've worn this suit in a race, so I'm very happy with it," Schipper said. "That's my fastest heat. Hopefully it will keep going the right way."

Trickett skipped the worlds, but there's still plenty of competition at the Foro Italico.

"Everyone seems to be swimming quite fast," Schipper said. "It will definitely be an interesting final."

Kukors, part of a youthful U.S. women's team, led the way in the 200 individual medley at 2:08.53 wearing Jaked's polyurethane suit. That was far faster than the championship record of 2:10.13, set two years ago by fellow American Katie Hoff, and also beat Julia Smit's American record of 2:09.34.

The 20-year-old Kukors was just eight-hundredths off Australian Stephanie Rice's world record of 2:08.45.

Hungary's Katinka Hosszu was next at 2:09.12, followed by Olympic gold medalists Rice (2:09.64) and Kirsty Coventry of Zimbabwe (2:09.90).

Germany's Paul Biedermann posted the top time in the men's 400 free at 3:43.01. China's Zhang Lin was next at 3:43.58, followed by Ous Mellouli of Tunisia at 3:43.78.

But Park, who won the 2007 world title in Melbourne and last year became South Korea's first Olympic gold medalist in swimming, got off to a sluggish start and only managed the 12th-best time, 3:46.04. The top eight advanced to the final.

American Peter Vanderkaay got through as the fifth qualifier (3:45.40).

Another meet record fell in the men's 50 butterfly, a non-Olympic event. Schoeman and Munoz both touched in 22.90, breaking Schoeman's 4-year-old mark of 22.96. They were shy of Munoz's world record, 22.43, set in April.

Serbia's Milorad Cavic, who lost to Michael Phelps by one-hundredth of a second in the 100 fly at the Beijing Olympics, was third at 23.04. Australia's Andrew Lauterstein was fifth-fastest (23.10), but Americans Tyler McGill and Matt Grevers failed to advance to the evening semifinals.

Australian relay swimmer Megan Nay planned to compete in the women's 400 free relay, one day after her brother was killed in a car wreck.

"Obviously, everyone is devastated at the news," said Ian Hanson, a spokesman for Swim Australia. "But the team will support her in whatever decision she makes."