OMAHA, Neb. — Dara Torres was back in the pool at the U.S. Olympic trials today, easily advancing out of the 50-meter freestyle preliminaries but losing her American record to Lara Jackson.

The 41-year-old was the third-fastest qualifier, finishing second in her heat to Jackson, who touched in 24.50 seconds. That broke the old mark of 24.53 set by Torres at last summer's U.S. nationals in Indianapolis.

Saturday night's finals were set to feature Michael Phelps vs. world recordholder Ian Crocker in the 100 butterfly, Katie Hoff vs. Kate Ziegler in the 800 free, and Gary Hall Jr. going for a spot on his fourth Olympic team in the 50 free.

Phelps needs to finish first or second to ensure he'll swim eight events in Beijing and have a chance at breaking Mark Spitz's record of seven gold medals from 1972. Crocker also must crack the top two to make the team in an individual event.

Torres swam a 24.72, hours after making an improbable fifth Olympic team by winning the 100 free Friday night.

"That was a pretty easy swim for me, so I'm pretty happy with my time," she said.

Jackson, a 21-year-old from El Paso, Texas, surprised herself by going six-tenths below her previous best.

"I'm shocked," she said. "It's awesome. But it's not about what you do in the prelims and semis. I've got to do it in the finals and make the team."

Jackson raced in a lane next to Torres, whose large goggles are older than most of her competitors.

"She's an awesome swimmer. To race next to her is an honor," Jackson said. "I read a quote from her where she said, 'At this level, it's all about racing.' She's right on about that."

Torres was still relishing her historic win the previous night.

"Obviously, I'm pretty excited right now," she said. "I don't think it's really sunk in yet."

Jessica Hardy was second-fastest in the prelims in 24.63, followed by Lacey Nymeyer and Kara Lynn Joyce.

"That's a best time. I did a Jacuzzi warmup (sitting in the hot tub)," Hardy said. "I was half-asleep this morning. I wasn't expecting that time. I'm very surprised."

Among those failing to advance were 2004 Olympians Dana Vollmer (25th) and Amanda Weir (27th), who made the final four years ago at trials.

Two-time Olympian Erik Vendt was the only man under 15 minutes in the grueling 1,500 free prelims, finishing in 14 minutes, 50.24 seconds to lower the trials record set by Larsen Jensen in 2004.

"I'm happy to be up at the top of the times," Vendt said. "I was not expecting to go that fast. I really didn't want to go that fast. I just put in the effort I thought was necessary. I'm pretty excited about tomorrow night."

Vendt was under Jensen's American record pace through 800 meters before pulling back to save something for Sunday's final.

"His speed has come along a lot in the past year," Jensen said. "He's going to be tough, no question about it."

Chad La Tourette qualified second-fastest in 15:02.78. Peter Vanderkaay was third and Jensen advanced in fourth with a time of 15:11.99.

"I'd like to go a best time (in the final)," Jensen said. "I haven't done a best time in this since Athens. I've been close but not quite on it."