Now that Regan Smith is 20 years old, she said it feels strange not to be among the youngest American swimmers at the world aquatics championships. She may be older this time, but the Olympian from Lakeville proved she is still golden, winning the women's 100-meter backstroke Monday in Budapest.

Smith led through the entire race and finished in 58.22 seconds, repelling a challenge from Canada's Kylie Masse at Duna Arena. Masse was in hot pursuit throughout, taking silver in 58.40. American Claire Curzan, who will join Smith at Stanford this fall, was third (58.67).

The U.S. has dominated the first three days of the swimming competition at the world championships, with 18 total medals and seven golds. Australia stands second with five medals, including two golds. Katie Ledecky also won gold for the U.S. on Monday, earning her fourth world crown in the women's 1,500.

In Sunday's semifinals of the 100 back, Smith topped the field in 57.65 — the sixth-fastest performance in history, and not far behind Kaylee McKeown's world record of 57.45. Smith, who held that record before McKeown broke it last year, said she was "hurting a lot'' in the late stages of Monday's final. Under heavy pressure from Masse, Smith was happy to get the win, if not the record.

"I knew it was a really close race,'' Smith said in a post-race interview on the Olympic Channel. "I was just telling myself to get my hand on the wall, and I did it.''

McKeown, of Australia, won the 100 back at the Tokyo Olympics but chose not to swim that event at worlds so she could focus on the 200 individual medley. She earned silver in that race Sunday.

The gold was Smith's third at a world championships. In 2019, she won the 200 back while recording a world-record time in the semifinal (2:03.35). She set another world mark in the 100 back (57.57) as part of the U.S. foursome that won the 4x100 women's medley relay.

In Budapest, Smith has returned to the city where she competed in her first world championships in 2017. She was a nervous 15-year-old at that meet, the youngest swimmer on the U.S. team. In the five years since, she has won three world titles, three medals at the Tokyo Olympics and two NCAA championships as a freshman at Stanford.

"It's just weird to be on the older side of things,'' Smith told the Olympic Channel after Monday's race. "It's just so crazy. But I'm really proud to get another gold medal at the world championships. It's just really special.''

The 100 back was the first of three individual events Smith is qualified to swim. She is also entered in the 50 back and 200 butterfly, which will be a challenging schedule if she races in both. The preliminaries and semifinals for both of those events are Tuesday, and both finals are Wednesday.

Gophers swimmer Bar Soloveychik, who is representing Israel at the world championships, placed 17th in the preliminaries of the men's 800 freestyle Monday and did not advance to the final.