Kihira Rika retained her title at the ISU Four Continents Figure Skating Championships at the Mokdong Ice Rink in Seoul.
Victory was not certain for the Japanese national champion after she missed her first triple Axel jump, costing her valuable points.
But the defending champion went on to land a triple Axel-double toe loop combination as she took victory by just over nine points from home favourite and Winter Youth Olympic Games champion You Young.
The 15-year-old Korean edged out Bradie Tennell, second after the short program, for the silver medal despite the American earning a season's best free skate score.
Triple Axel returns to centre stage
With European skaters not eligible, the Four Continents gave skaters a chance to take a big competition win this season in the absence of the '3A' - Russia's dominant trio of Alena Kostornaia, Anna Shcherbakova and Alexandra Trusova.
Sakamoto Kaori was fourth after the short program and attempted a quad jump - a quad toe loop - in her free skate.
But the 2018 Four Continents champion fell and under-rotated on the attempt and ended up in fifth place.
The triple Axel ended up taking centre stage with Kihira, You and Higuchi Wakaba including it in their free skates.
Higuchi started her routine with it but the Japanese fell in her attempt and ended up fourth overall, 15.51 points off third place.
You was the penultimate skater to take to the ice and opened with a solid triple Axel which had the home crowd roaring with delight.
Skating to a medley from the soundtrack to Evita by Andrew Lloyd Webber, the Lausanne 2020 gold medallist continued with a fine triple Lutz-triple toe loop combination.
The Seoul native went on to complete a clean skate for a personal best free skate score of 149.68 and a new career-high total of 223.23.
That saw her overtake Tennell by just a quarter of a point and take the lead with just one skater to go.
With the crowd in the arena still cheering You's performance, her training partner Kihira prepared to start her skate.
Leading by five points after the short program, the 17-year-old opened with a triple Salchow but then singled what should have been a triple Axel.
The three-and-a-half rotation jump had also cost her dear at the last World Championships, but the teenager did well to regain her focus.
Kihira was able to land it later in combination with a double toe loop to significantly boost her technical elements score as she completed the rest of her routine cleanly.
Skating to 'International Angel of Peace', she scored 151.16 to post a season's best total of 232.34 points and clinch overall victory by 9.11 points.
That made it five consecutive wins for Japan in the ladies' event with Japanese women winning 10 of the last 13 Four Continents titles.
Kihira told ISU.org, "I became a little bit impatient because of my first mistake in the Axel. But I was able to re-calculate and re-assemble the structure of my performance.
"I tried to switch my mind and focus on the next element right away after I did my first mistake. It was good experience for me to prepare for the next competition." - Kihira Rika
You was delighted with her performance, saying, "I was very happy to do the triple Axel and then there were no mistakes in my jumps. I focused on a clean performance. Especially since this event was held in Korea I had a little pressure.
“I’m the first Korean skater to have a medal since Yuna Kim and I feel very honoured to be first since her and to achieve this in my home country.”
Near perfection will be required for Worlds medal hope
Kihira is fourth on the season-high totals list behind the all-conquering Russian youngsters.
And she still has ground to make on the 3A with her Seoul score of 232.34 some way behind Kostornaia and Shcherbakova's respective totals of 247.59 and 240.02 from the Grand Prix Final, and Trusova's PB of 241.02 set at Skate Canada.
The Japanese fell attempting a quad Salchow at the Grand Prix Final, and she may need to bring it back in order to boost her chances of getting in amongst the Russians at the upcoming World Championships in Montreal, Canada from 16-22 March.