LONG BEACH, Calif. – Michael Phelps sure doesn’t look so unbeatable now.

For the second straight day, Phelps touched the wall second at the U.S. Olympic swimming trials – beaten Tuesday by another world-record performance.

Portland’s Ian Crocker eclipsed his own mark in the 100-meter butterfly to edge Phelps, whose quest to break Mark Spitz’s record of seven Olympic gold medals appears more daunting than ever after 17 races over the past week.

“I’ve never been under that kind of stress in a meet before,” Phelps said. “I’m very relieved it’s over.”

If he thinks this was bad, just wait until the Olympics. Ian Thorpe and the rest of the world’s top swimmers will be waiting, eager to deny Phelps his place in history.

Speaking of Athens, Gary Hall Jr. will be on hand to defend his title as the world’s fastest Olympic swimmer after beating rival Jason Lezak in the 50 freestyle. But Brooke Bennett is done, failing to earn a chance to win her third straight gold in the 800 free.

Crocker led at the turn and withstood a challenge coming down the stretch, touching the wall in 50.76 seconds – the sixth world record of the trials. Phelps finished in 51.15, the fourth-fastest time in history but not fast enough.

“He definitely took me out in the first 50,” Phelps said. “I was too far behind and couldn’t play catch-up.”

Crocker’s time beat the mark of 50.98 he set at last year’s world championships in Barcelona.

Aaron Peirsol beat Phelps in the 200 backstroke final Monday – also setting a world record.

Hall will be trying to win his second straight gold in the 50 free, having tied Anthony Ervin at Sydney four years ago. Hall equaled the sixth-fastest time in history at 21.91, while Lezak touched second in 22.05.

Their rivalry was spurred on by trash-talking and other antics by Hall, Lezak and their representatives. But the two seemed to get along just fine after the 50, shaking hands and exchanging smiles.

“There’s nothing between us in the first place,” said Lezak, who beat Hall in the 100 free. “We’re both here to do a job. I did the job I was looking to do and I’m sure he’s happy with what he did.”

Ever the showman, Hall climbed atop a starting block and bowed to the cheering crowd. Then, still dripping wet and wearing nothing but his suit, he walked into the stands to hug his wife. Later, he strolled around the deck wearing a stars-and-stripes boxing robe, in keeping with his belief that the 50 is like a heavyweight fight.

“I just wanted to get to the other end of the pool,” Hall said. “Last one there is a rotten egg.”

Hall has eight sprinting and relay medals from the last two Olympics. He’ll have a chance to add to that haul in Athens, becoming part of the first father-son duo to both qualify for three Olympics.

Bennett, who succeeded Janet Evans as the queen of American distance swimming, finished third behind Diana Munz and Kalyn Keller in the 800 free to miss a spot on the Olympic team.

Bennett won the 800 at Atlanta and pulled off a 400-800 double at Sydney four years ago. But she hasn’t been the same swimmer since undergoing surgery on both shoulders in 2001, struggling just to get out of the preliminaries.

“I gave it a good fight,” Bennett said.

Munz, the 400 silver medalist in Sydney, won a great sprint to the wall in 8:26.06, barely edging Keller (8:26.33). Evans was third at 8:29.39 – her best time since surgery but nearly 10 seconds slower than the winning time in Sydney.

While Phelps became the first U.S. swimmer to qualify in six individual events at the Olympics, the last two days cast serious doubts on his quest to break Spitz’s record at the 1972 Munich Games.

Phelps and his coach, Bob Bowman, plan to decide in the next day or two whether to swim all six individual races in Athens, or go with a lighter schedule that might keep him stronger but give him fewer chances to beat Spitz.

Phelps has qualified for at least one relay and also wants to swim the other two, giving him as many as nine races at the Olympics.

Crocker established his supremacy in the 100 butterfly with an upset of Phelps at the 2003 world championships. Both swimmers eclipsed Phelps’ previous world record on that night – a race that prompted Phelps to put up a picture of Crocker in his bedroom as extra motivation.

It didn’t help at the trials, where Phelps swam the last of his 17 races during a grueling, weeklong stretch.

“Michael is a phenomenal swimmer and he’s trying to do something really special,” Crocker said. “He is attracting attention to this sport we haven’t had in a long time and it’s a healthy thing.”

Then again, he’s hardly the only swimmer at these trials worth noticing.

Brendan Hansen set two world records in the breaststroke, while Peirsol, Crocker and Amanda Beard have as many as Phelps.

“Brendan Hansen, Aaron Peirsol and myself deserve similar attention,” Crocker said.

The 21-year-old laid down a challenge to Phelps, vowing to take the world record even lower in Athens.

“I promise,” Crocker said.

Margaret Hoeltzer won the 200 backstroke in 2:11.88, benefiting from the absence of American record-holder Natalie Coughlin. She skipped the event to focus on the 100 freestyle and 100 backstroke. The second spot on the team was claimed by Kristen Caverly at 2:12.70.

“I don’t think it’s sunk in yet,” Hoeltzer said. “Just to see No. 1 by your name and know what that means, wow!”

Jenny Thompson heads to the women’s 50 free final as the top qualifier. She won her semifinal heat at 25.11.

Kara Lynn Joyce, an upset winner in the 100 freestyle the previous night, was second fastest at 25.23. Coughlin, swimming the event just for fun, moved on with the No. 5 time (25.39).

Thompson, a 10-time medalist who will be competing in her fourth Olympics, bounced back from a disappointing fifth-place finish in the 100 free.

“After last night, I had a little more motivation,” she said.

Erik Vendt went fastest in preliminaries for the grueling 1,500 free at 15:18.15. But Chris Thompson, the bronze medalist from Sydney, failed to make the team after fracturing both elbows during a training fall two months ago. While the elbows have mostly healed, he wasn’t able to resume full training until the last two weeks.

“I was getting better,” said Thompson, who was 11th fastest at 15:40.84. “I just didn’t have enough time.”

The trials conclude Wednesday evening with finals in the women’s 50 free and the men’s 1,500 free.