ST. PAUL, Minn. - Next time, Mirai Nagasu is going to have to remember those glasses.

Nagasu delighted the crowd — and herself — with a refreshing and entertaining show at the U.S. Figure Skating Championships on Saturday night. The best part? The 14-year-old had no idea she’d become the second-youngest woman to win the U.S. title until coach Charlene Wong told her.

“I didn’t have my glasses on,” Nagasu said. “Charlene was like, ‘Oh my god.’ I was like, ‘What?’ And she was like, ‘You won!’ And I was like, ‘Whaaat!”’

She clapped her hands to her face and broke into a grin as the crowd laughed.

“I am very excited and speechless for words,” she said.

Figure skating has been in the doldrums since Michelle Kwan and Sasha Cohen decided to try new things, in desperate need of a new star. Well, Nagasu appears to fill that bill. She’s a breath of fresh air, both on the ice and off.

“She really is just a regular 14-year-old who has a special gift,” Wong said. “I think this is only the beginning of many good things for her.”

Nagasu can’t go to the world championships in March because she’s too young. Skaters now must be 15 by the previous July 1, and she won’t even turn 15 until April 16. Rachael Flatt, who finished second, missed the cutoff by three weeks and will have to sit worlds out, too.

Ashley Wagner finished third, and she is eligible for worlds. She and Bebe Liang were selected for the world team along with Kimmie Meissner, whose stunning decline continued with a seventh-place finish.

“I’m not necessarily disappointed about not being able to go to worlds,” said Nagasu, who will go to the junior world championships. “I definitely don’t think I’m ready for anything that high yet.”

She’s selling herself short. Nagasu won the junior title as a complete unknown last year — she’d never even made it as far as the final qualifier before — and wasn’t the 14-year-old everyone expected to win this week.

But she skated with a breeziness that enchanted the audience and the judges. Only Tara Lipinski in 1997 was younger when she won the title, and the Olympic gold medalist only has Nagasu beat by about a month.

Skating to “Coppelia,” the story of a doll that comes to life, Nagasu played on her youth and size — she’s 4-foot-11. She fell on her opening jump, a double axel, but very quickly regrouped.

Nati Harnik / AP John Baldwin, right, proposes to dance partner Rena Inoue after they had finished their dance in the pairs free skating segment Saturday.

“The fall on the double axel was like a kick in the butt,” she said. “After that, I was like, ‘Attack!”’

She performed perfectly in character, stiffly holding her arms out to the side like a lifeless doll. As she was wound up, she jerked her arms and her torso, looking like a doll coming to life. When she bounced upward, the audience laughed.

Fully alive, she danced across the ice with light and airy footwork. She landed six triple jumps, three in combination, and showed great stamina by picking up speed as the program went along.

Perhaps most impressive is that this is the first time Nagasu has competed a 4-minute program. She spent the fall on the junior international circuit, where she only had to do a 3½-minute routine.

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“I can’t put it into words,” Wong said of how much Nagasu has accomplished in such a short time. “I’m just happy for her and happy for her family.”

Flatt’s skating was as bright as the smile that was on her face from the time she took the ice to the time she left it. In third place after the short program, she overtook Wagner with a routine that included playful footwork and seven triple jumps.

Wagner was powerful, making even her jumps at the end of the program look easy. She used everything in her performance, including her hair. Her ponytail bobbed and swished, and she swung it around for emphasis a couple of times.

“I’m going to have to act like a teenager,” Wagner said. “I’m going to worlds and I’m so excited!”