Alysa Liu never expected to win the world championships. After all, the 19-year-old figure skater retired from the sport three years ago, only returning to training again a year ago and international competition six months ago.

Alysa Liu became the first American women's figure skating world champion in nearly two decades Friday night, dethroning three-time defending champion Kaori Sakamoto with a brilliant free skate that earned her a standing ovation inside TD Garden.

In her first figure skating career, the one she ended with a retirement three years ago at age 16, Alysa Liu won national titles, made history as the youngest this and the youngest that, did landmark jumps for a U.