The first time Regan Smith raced at the world championships, she had no idea what to expect. The Lakeville teen was only 15 then, a wide-eyed girl just learning how to compete on the global stage.

Her goal two years ago was to gain experience. Friday, Smith entered her second world championships seeking something bigger — and she delivered a world record in the 200-meter backstroke. In a performance that wowed the swimming world, Smith blazed through the semifinals in Gwangju, South Korea, finishing in 2 minutes, 3.35 seconds.

Smith’s time chopped more than half a second off the previous mark of 2:04.06 set by Missy Franklin in a gold-medal swim at the 2012 Olympics. With a world record in her pocket, she will try to add a world championship Saturday, when she races in the final about 6:30 a.m. Minnesota time.

“I’m in shock,” Smith told reporters. “I really don’t believe it. I didn’t think I’d ever do that. It’s crazy.

“I’m really happy, very happy with what I was able to do. I was hoping to slip under 2:06. [The swim] greatly exceeded my expectations.”

The youngest member of the U.S. team by more than three years, Smith has been a star in the making since she began breaking national age-group records when she was 13.

A senior-to-be at Lake­ville North, she is ranked second in the world in the 100 backstroke but has made her greatest impact in the 200 back.

After finishing eighth in the 200 back at the 2017 world championships, Smith said two additional years of experience left her feeling comfortable and confident this time. She broke her own world junior record in Friday’s preliminary heats, clocking 2:06.01 to finish 2.33 seconds ahead of the next-fastest competitor.

Smith wasn’t the only one stunned by her time in the semis. U.S. teammate Caeleb Dressel, who broke Michael Phelps’ world record in the 100 butterfly Friday with a semifinal swim of 49.50, raved about her race.

“[The U.S.] had a really good night tonight, especially with Regan,” said Dressel, who took down a record Phelps set in 2009. “That was phenomenal. I thought that was one of the top three toughest world records [to break] on the women’s side, and she just crushed it.”

With one year to go until the 2020 Olympics in Tokyo, Smith already has been compared to Franklin. The record Smith broke Friday was the last world mark held by the five-time Olympic gold medalist, who retired from swimming last year.

Franklin, via Twitter, passed the torch graciously.

“I truly couldn’t be happier seeing my World Record go to someone who I believe at the bottom of my heart is one of the greatest inspirations and kindest humans in the world,” Franklin wrote. “Congrats my dear @regan­esmith4. Thank you. For sharing your gift with us. You’re beyond a joy to watch.”