OMAHA, Neb. — Michael Phelps just missed setting another world record at the U.S. Olympic trials.

Natalie Coughlin and Aaron Peirsol showed him how to do it.

Racing about 10 minutes apart, Coughlin and Peirsol broke their own marks in the 100-meter backstroke today on another lightning-quick night at a temporary pool in America's heartland.

Their records were the fifth and sixth of the meet — with five days to go. Both Coughlin and Peirsol were wearing the Speedo LZR Racer, which upped its tally of world marks to 44 since debuting in mid-February.

Phelps made a dogged run at perhaps the most impressive record on his resume, the time of 1 minute, 43.86 seconds from the 200-meter freestyle at last year's world championships. He was right on pace as he powered toward the wall, but he touched with only the third-fastest time in history, 1:44.10.

Then it was time for Coughlin and Peirsol to shine.

Coughlin became the first woman to break 59 seconds, just one day after she reclaimed the world record in the preliminaries. She touched in 58.97, locking up the first of perhaps as many as six races she could swim in Beijing.

Peirsol showed he's still king of the backstroke, beating a strong field and his own record in the 100 back at 52.89, ahead of the 52.98 from last year's worlds.

Matt Grevers took second just ahead of Ryan Lochte, who dropped a spot in the 200 free final — and another chance to race Phelps — to give himself a better chance to qualify in the backstroke. The move didn't pay off; Lochte came on strong over the final 50 but touched in 53.37, behind Grevers' 53.19.

Phelps returned to the pool about 50 minutes after the 200 free, posting the fastest time in the semifinals of the 200 butterfly at 1:54.02. He'll head to Wednesday's final as a big favorite in yet another event which has his name at the head of the record book.

In the night's other final, Jessica Hardy earned her first trip to the Olympics by winning the 100 breaststroke. The 21-year-old was under world-record pace at the flip but faded on the return lap. Still, she managed to win 1:06.87.

Megan Jendrick, who won two golds at the Sydney Olympics as Megan Quann but just missed making the team four years ago, claimed the expected second spot for Beijing in 1:07.50 — one-hundredth of a second ahead of Tara Kirk.

Three-time Olympian Amanda Beard missed her first chance to get back on the team, finishing sixth in 1:08.80. She considers the 200 breaststroke her better event.