OMAHA, Neb. (AP) — Ryan Lochte and Michael Phelps stayed on course for their second showdown at the U.S. Olympic swimming trials on Tuesday. Janet Evans' first appearance in the meet was brief, with the 40-year-old former Olympic champion failing to advance to the 400 freestyle final.

Lochte qualified fastest in the 200-meter freestyle preliminaries, exploding off the final turn to take the lead and cruise into the wall at 1 minute, 48.14 seconds. He's the world champion in the event, having beaten Phelps for the title last year in Shanghai.

Charlie Houchin, a 24-year-old from Raleigh, N.C., who was 77th in the 200 free at the 2008 trials, was second-fastest at 1:48.15. Swimming in the heat before Lochte, Phelps qualified third at 1:48.31. He is the Olympic champion and world record holder.

Evans finished seventh in her heat at 4:21.49 — 6.81 seconds behind 19-year-old winner Danielle Siverling. But Evans, who won the 400 free as one of her three golds at the 1988 Olympics, was merely using the event as a warm-up for the 800 free. She is a long shot in that grueling event after a 15-year absence from the sport.

Budding star Missy Franklin and two-time Olympic champion Natalie Coughlin advanced in the 100 backstroke prelims.

Lochte got the better of Phelps in their first final at trials when he won the 400 individual medley on Monday. Phelps finished second, and they both secured spots for London.

Phelps has set himself up for another eight-event program in London — something he insisted he wouldn't do again after the Beijing Games.

"It's not an easy program, but we're going to try to do some things here," he said. "The biggest thing is really how I hold up all week. I was definitely happy with getting last night out of the way early. It wasn't the easiest race. But this morning felt pretty comfortable, so hopefully we can just keep everything rolling for the rest of the meet."

Can Phelps repeat his historic haul of eight golds?

"Anything can happen," he said. "You've got to be in the right place at the right time."

Also moving into the 16-man evening semifinals were Conor Dwyer (fifth) and Peter Vanderkaay (sixth). They already earned berths on the U.S. team in the 400 freestyle Monday night.

Davis Tarwater, who narrowly missed making the 2008 Olympics when he was third in the 200 butterfly, was eighth. Ricky Berens, bidding for his second straight Olympic spot, was ninth.

Lochte returned later for the 100 backstroke and qualified nearly a second behind fellow 2008 Olympian Matt Grevers. He touched in 52.94 to Lochte's 53.92.

Lochte was breathing hard coming off the deck after his double.

"The 100 back hurt worse than the 2 free," he said. "The 2 free was really just smooth. I'll decide with my coach if I swim the 100 back again tonight or not. It's still up in the air."

Grevers, the 2008 Olympic silver medalist, hoped to see Lochte in the semifinals.

"The Olympics are all about racing the best in the world," he said. "I'd be sad if he wasn't in it because I'd know one of the best in the world would be missing out."

Swimming her first event of the eight-day meet, Franklin was the top qualifier in 59.54 seconds, easily moving the 17-year-old from Colorado into the evening semifinals.

"I had some first-race jitters," she said. "But I'm super, super happy with my time. It felt awesome."

Franklin saw the sign under the massive scoreboard above the pool as she stroked to the opposite end of the pool.

"It was U.S. Olympic Team. Talk about motivation. That helped me get my tempo up the last 25," she said. "I was nervous for my first race. But right now, I feel good."

Franklin led a quartet of teenagers who represent the U.S. future in the event. Rachel Bootsma, an 18-year-old from Minnesota, was second at 59.69, making her and Franklin the only women to go under 1 minute.

Elizabeth Pelton, an 18-year-old from Connecticut, was third at 1:00.55. Olivia Smoliga, a 17-year-old from suburban Chicago, was fourth-quickest at 1:00.66.

Coughlin advanced in fifth at 1:00.71. She was the first woman to break 1 minute in the event and formerly held the world record.

The top 16 in the semifinals move on to Wednesday's final, where only the top two earn berths for next month's Olympics.

World champion Rebecca Soni led the way in the 100 breaststroke, coming on strongly over the final 50 meters to win her prelim heat in 1:06.33.

Breeja Larson showed no nerves in her first Olympic trials, turning in the third-fastest time in the world this year to qualify second-quickest at 1:06.52. The sophomore at Texas A&M didn't start swimming competitively until age 17 in her hometown of Mesa, Ariz.

Jessica Hardy, who won the 100 breast at trials four years ago only to lose her spot on the Olympic team because of a failed doping test, was third at 1:07.25. Hardy served a one-year ban after an arbitration panel agreed with her contention that a tainted nutritional supplement was to blame for her positive test.

Still, she battled anger and depression during the fight to clear her name.

"This is the first time I felt like I can actually have a happy ending," she said. "I can relax and finally have fun and feel grateful."

Soni caught Hardy's time as she was waiting to come on deck.

"She did really well. It gets you kind of pumped up," she said. "The times are getting faster and faster every year. I definitely have to keep my 'A' game going."

Amanda Beard, the 1996 Olympic silver medalist in the 100 breast, qualified seventh for the evening semifinals. The 30-year-old mother of one is trying to make her fifth Olympic team, but the 100 is not her best event and she will have to pick up the pace to make the eight-woman final.

"I think my chances are great," she said. "But this isn't my life. My life doesn't just revolve around swimming. I won't be too devastated walking away and saying I competed at my fifth Olympic trials. I'll look at it as a success and go on a nice vacation with my family."