OMAHA – The buildup started well before the U.S. Olympic trials did. As the field for the women's 100-meter backstroke began to take shape, a USA Swimming meet preview said the event was "set up to be one of the most talented fields of any race ever swum on US soil," calling it "an all-time race in the making."

The first two rounds went to Lakeville's Regan Smith, who dominated Monday and moved within one step of her first Olympic team. The top seed — and the world-record holder until Sunday — set a U.S. Open record of 57.92 seconds in the semifinals, the second-fastest time in the world this year. Smith easily won her heat and was .58 faster than Olivia Smoliga, whose time of 58.50 was next best.

Blaine's Isabelle Stadden also is among eight women who will swim in the finals of the 100 backstroke tonight at CHI Health Center. Stadden's time of 58.99 was a personal best and tied for fourth-fastest in the semifinals.

Olympic trials on TV: 7 p.m., NBC

The winner will make the U.S. team for the Tokyo Olympics. The second-place finisher is likely to be named to the team later in the week.

"It's awesome," Smith said of her semifinal swim. "I haven't been under 58 [seconds] in a very long time. It feels great.

"I'm in a good spot right now, but I don't want to get too far ahead of myself. That wasn't the final. I've got to do it again [Tuesday]."

Three more athletes won their finals Monday to claim spots on the Olympic roster. Six-time Olympic medalist Katie Ledecky triumphed in her first final of the trials, easily winning the women's 400 freestyle in 4:01.27. Michael Andrew — who set an American record in the men's 100 breaststroke Sunday — won the final, and Torri Huske set a U.S. record of 55.66 to finish first in the women's 100 butterfly.

Smith showed she is still the woman to beat in the 100 back, which includes five of the six fastest American women ever to compete in the event. Smith held the world record of 57.57 for two years until Australia's Kaylee McKeown broke it Sunday. Kathleen Baker was the 2016 Olympic silver medalist, Smoliga was a 2016 Olympian and Phoebe Bacon and Rhyan White are rising young stars.

Smith has occasionally wrestled with her backstroke over the past year, saying her signature stroke was "not feeling good" last summer. Though she called her journey to Monday's races "a little bit of a rocky road," she predicted it would be worth the many painful hours in the pool once she reached the Olympic trials.

She admitted to some nervousness in her first two swims Sunday, when she competed in the 100 butterfly on the opening day of the trials. Smith did not swim as well as she wanted to in the first 50 meters of both those races, but she displayed late speed that left her feeling optimistic for the 100 back.

"[Sunday] was a great learning experience," Smith said. "It set me up very well."

Smith's father, Paul, said Regan was "supremely confident" as she walked to the pool Monday morning. Though she had reached Monday night's finals of the 100 fly, it is not one of her top events, so she decided to scratch from the final to pour all her energy into the 100 back.

Relaxed and ready, Smith led the entire way in her preliminary heat and finished in 58.35, .53 of a second ahead of her closest competitors. That was the fourth-fastest time this year. In the evening semifinals, Smith went faster.

She led at the halfway point in a time of 28.24, then blazed through the second 50 in 29.68 to break Baker's U.S. Open record by .08.

Tuesday's final could well be an all-time race, as predicted before the trials. It will take another swift time to win, but Smith likes where she is.

"I couldn't have asked for a better day," she said. "I'm very pleased."