Czisny's polish was countered by the unraveling of Mirai Nagasu, 17, who led by 0.85 of a point at the start of the free skate at the U.S. Figure Skating Championships but committed critical - and inexplicable - mistakes near the end of her program.

She ended up in third place, behind Czisny and Rachael Flatt, 18, who jumped from third to second place despite making a handful of mistakes of her own.

Czisny, who finished 10th at this event last year, earned the night's best score and 191.24 points overall. Flatt, who finished seventh at last year's Olympic Games, scored 183.38. Nagasu ended up with 177.26.

Nagasu's faltering proved doubly costly. Only the top two U.S. women earned trips to the March world championships in Tokyo, which means Nagasu, who finished fourth in last year's Winter Games, will stay home.

"I was really nervous before I went out there," Czisny said. "I knew exactly what I had to do. Before every jump, I thought about what I was here for, and what my goals were. I fought for every single thing."

For Czisny, the standing ovation began before she stopped her final spin. A year after a calamitous nationals, she stayed on her skates in back-to-back programs and capped a season that included a victory in the prestigious International Skating Union Grand Prix Final in December. She nearly fell attempting a triple loop but hung on, hit her other jumps and showed off difficult spins.

"It went so fast," she said. "I landed the last triple toe before I was ready for the program to be done."

Czisny said she hopes she's on her way to kicking her reputation for inconsistency. In two previous trips to the world championships, in 2007 and 2009, she has performed poorly, finishing 15th and 11th.

"This whole season is me as a new skater," she said. "I've been a lot more consistent in all of my competitions this season, doing what I have to do when I have to do it, and I plan to do that at worlds."

Nagasu looked mortified after her skate. She got penalized for under-rotating a couple of jumps, stumbled out of a double Axel and badly muffed her entry to her flying sit spin - a critical mistake that caused her to lose credit for that element.

"If I'm not satisfied, or every single run-through isn't perfect, I let that get to me instead of going out there and attacking," Nagasu said. "I just let my nerves get the best of me. . . . I can't believe I messed up on a spin. A spin!"

Flatt hoped to electrify the crowd and leap from third to first, but from the start she did not look at the top of her game. She came out of her opening combination short and turned a planned triple Lutz into a double.

"Obviously, it was a little bit disappointing," Flatt said. "I guess I was a little bit tired. I had to skate pretty late, so that was a bit tough . . . [but] I accomplished what I needed to here to make sure I could move on to the rest of my season."

Alexandria's Ashley Wagner, in seventh entering Saturday, claimed sixth with 165.36. Silver Spring's Kristine Musademba, who was 13th after the short program, finished 15th with 123.53 points.

Given that she missed weeks of training before the start of the season because of bizarre full-body tremors - which she has brought under control with therapy - and faced an untimely bout of flu-like symptoms this week, Wagner said, she was pleased with the outcome.

"I have had a traumatic year," she said. "Something was around the corner wherever I went. I'm thinking I'm getting all of the bad experiences out of the way . . . for the rest of my life I should be set."

Other results: Meryl Davis and Charlie White won their third straight U.S. championship in dance, earning 185.48 to top Maia Shibutani and Alex Shibutani, who scored 173.18. Gambrill's Ian Lorello and partner Isabella Cannuscio got sixth with 136.55; Meredith Zuber and Centreville's Kyle Herring were ninth (118.06); Vienna's Ginna Hoptman and Pavel Filchenkov finished 10th with 117.53; and Katherine Pilgrim and Gambrill's Alex Lorello placed 15th with 80.39.