OMAHA – When she arrived in Omaha for the U.S. Olympic swimming trials, Regan Smith held two world records. By the time she swam her first race, she had only one.

Smith, of Lakeville, was walking to the pool Sunday when her father, Paul, told her that her world record in the 100 backstroke had fallen at a meet on the other side of the globe. Kaylee McKeown broke it at the Australian Olympic trials, clocking a time of 57.45 seconds, .12 seconds faster than Smith's two-year-old mark.

Sunday, Smith qualified for the finals in the 100 butterfly at CHI Health Center, then chose to scratch Monday's final to conserve energy for other races — including the 100 back. Instead of being disappointed at losing the record, she felt motivated.

"I'm genuinely excited for her," Smith said of McKeown. "It makes me look forward even more to the 100 back [Monday] and Tuesday."

On the first day of the trials, Smith competed in the preliminaries and semifinals of the 100 fly, the first of four events she plans to swim. Her semifinal time of 57.73 put her into the eight-person final Monday night. But the preliminaries of the 100 back are Monday morning, and the semifinals are Monday night, which would have made for a very crowded schedule.

The 100 back is one of the most anticipated events at the trials, featuring six of the fastest American women to ever swim it. With her three best events ahead of her, Smith put the 100 fly behind her on a night when the winners of the first three finals secured places on the U.S. roster for the Tokyo Olympics.

Chase Kalisz, the 2016 Olympic silver medalist in the men's 400 individual medley, won that race to ensure his return to the Summer Games. Kieran Smith won the men's 400 freestyle, and Emma Weyant pulled off a dramatic finish to win the women's 400 individual medley.

Two American records were set on the trials' opening day. Torri Huske lowered the mark in the women's 100 fly with a semifinal swim of 55.78. Michael Andrew broke the American record in the men's 100 breaststroke in the preliminaries, then broke it again with a 58.14 in the semifinals.

Smith said goodbye to the world record of 57.57 she set in the 100 back as part of the 4x100 medley relay at the 2019 world championships. McKeown had come close to breaking it last month, when she swam a 57.63 at a meet in Sydney.

She told Australian media it was "a dream come true'' to make the Olympic team, but McKeown said she wasn't shooting for Smith's record at the trials.

"I wouldn't say it was a goal to break the world record,'' she said. "I'm more of a process-orientated person than times, and it just so happened that I nailed all those little pinpoints that we were going for.''

Smith remains the world record holder in the 200 back, a mark also set at the 2019 world championships. She is the top seed in both backstrokes at the Olympic trials and was seeded fifth in the 100 fly.

Before the meet, Smith already was thinking about scratching the final of the 100 fly if she made it. It was her least likely chance to make the Olympic team, and swimming the final would have given her three races Monday, with both the 100 fly final and the 100 back semifinal in the evening session.

Though bigger things lie ahead, Smith was glad to race twice Sunday.

"It was a good opportunity to get into the meet and shake opening jitters,'' Smith said. "I wish I had executed better going out, but I'm happy with my back-end speed. It bodes well for my bigger events this week.''