LONG BEACH, Calif. (AP) – The challenges just keep coming for Michael Phelps.

The world’s best swimmer couldn’t keep pace with Aaron Peirsol leaving the final turn in the 200-meter backstroke, and lost for the first time at the U.S. Olympic swim trials Monday night.

Peirsol pulled away on the final lap to win in a world record 1 minute, 54.74 seconds – breaking his own mark of 1:55.15 set two years ago. Phelps earned the other Olympic berth, finishing second in 1:55.86.

His next challenge comes Tuesday night in the 100 butterfly final, the last of Phelps’ six individual races at the eight-day trials. Like the 200 back, it will be another match race: Phelps vs. world record holder Ian Crocker.

Crocker was the fastest semifinal qualifier in 51.25 seconds. Phelps won his heat in 51.89.

“I love going fast. I love surprising myself,” Crocker said. “That’s my thrill. I’m real interested to see how fast I can go, and I’m real interested to see where Michael is at, too.”

On Tuesday morning, Jenny Thompson was top qualifier in the 50 freestyle at 25.15. Kara Lynn Joyce, an upset winner in the 100 freestyle the previous night, was second at 25.16, and Natalie Coughlin also advanced to the semifinals with the fourth-fastest time (25.49).

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.

“I felt good this morning, surprisingly,” she said. “After last night, I had a little more motivation.”

Erik Vendt went fastest in preliminaries for the grueling 1,500 free at 15:18.15. “I’m right where I wanted to be,” he said.

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 do regular training until the last two weeks.

“I’m really excited,” said Phelps, who succeeded in breaking the 52-second barrier in the semifinals. “Hopefully with some good rest, him and I and the rest of the field will have a good race.”

Phelps keeps a photo of Crocker on his bedroom wall as motivation. He may need to add one of Peirsol, who has defeated him in their last three meetings, including twice at a meet in Santa Clara in May.

“I don’t ever want to lose my race,” said Peirsol, the silver medalist in Sydney who hasn’t lost the 200 back since then. “I love that thing.”

Peirsol and Phelps were both under world record pace for the first three laps, matching each other nearly stroke-for-stroke. Then Peirsol came off the final turn faster, and Phelps said that cost him the race.

“It’s going to make me go back to the drawing board and try to change some things,” Phelps said. “It gave me sort of a message. I knew what I’m trying to do isn’t easy. No one said it was.”

Phelps bounced back to win the 200 individual medley, making him the first American male to qualify for five individual swimming events at an Olympics. It was his third race of the night, all in just over an hour.

At the Athens Games, he wants to break Mark Spitz’s record of seven gold medals.

Phelps won the 200 IM in 1:56.71 – 0.77 seconds off his own world record. Ryan Lochte took the second Olympic berth at 1:59.71.

Amanda Beard is going to her third Olympics, having qualified in three events. She won the 200 breaststroke by nearly 5 seconds in a world record time of 2:22.44. That broke the mark of 2:22.96 set by Australia’s Leisel Jones, who had taken the record from Beard last week.

Caroline Bruce was the surprise runner-up, earning her first trip to the Olympics in 2:27.22. Former Olympians Kristy Kowal (third), Megan Quann (sixth) and Staciana Stitts (eighth) failed to qualify for Athens. Tara Kirk, already going to the Olympics in the 100 breaststroke, finished fifth.

There was another upset in the 100 freestyle when Kara Lynn Joyce held off Natalie Coughlin by four-hundredths of a second.

Joyce won with a time of 54.38. Coughlin was second in 54.42. They each qualified for the Olympics. Jenny Thompson was fifth at 55.03, but she could still land a spot on the relay team.

Maritza Correia finished fourth and became the first black woman to make the U.S. swimming team. She’ll be eligible for the relay.