July 2 (Bloomberg) -- Natalie Coughlin and Aaron Peirsol bettered their 100-meter backstroke world records last night at the U.S. Olympic Swimming Trials to book places on the team for the Beijing Games.

Coughlin, 25, lowered the women's mark to 58.97 seconds in winning the final at the Qwest Center in Omaha, Nebraska.

``It was nice to see fireworks and get that ticket to Beijing,'' Coughlin said after the pyrotechnics fired off to celebrate her world record. ``This is such an emotional meet that it is a relief to make the team. Now I can take a deep breath.''

Peirsol, 24, won the men's 100m backstroke final in a time of 52.89, shaving .09 second off the record he set at last year's world championships in Melbourne.

``It's a huge confidence booster any time I can come out on top of a field like that,'' said Peirsol, who won three gold medals at the 2004 Athens Olympics. ``It's the fastest heat I've ever been in. Sixth place would have medaled (in Athens). I feel like I have a huge weight off my back.''

Coughlin's swim lowered the women's 100-meter backstroke mark for the third time in two days.

Her previous record of 59.21 was broken June 30 by Hayley McGregory in a preliminary heat. Coughlin, who won five medals including two golds in Athens, regained the record less than two minutes later in her heat with a time of 59.03.

Coughlin beat Margaret Hoelzer by .24 second in yesterday's final, with McGregory finishing third in 59.42.

Matt Grevers finished second behind Peirsol in the men's race in 53.19, followed by Ryan Lochte in 53.37.

Six world records have been set at the trials. Michael Phelps also lowered his mark in the 400-meter individual medley on June 29, the same day Katie Hoff swam a record time in the women's 400m medley.

Also yesterday, Phelps won the men's 200m freestyle in a time of 1 minute, 44.10 seconds to qualify for his second event in Beijing and had the fastest time in reaching today's 200m butterfly final. Jessica Hardy won the women's 100-meter breaststroke in 1:06.87.

To contact the reporter on this story: Erik Matuszewski in New York at matuszewski@bloomberg.net

Last Updated: July 2, 2008 02:35 EDT