16-year-old Anna Shcherbakova took the lead with an excellent short program on a day of surprises at the ISU World Figure Skating Championships.
The three-time Russian national champion, who turns 17 on Sunday, landed a difficult triple Lutz-triple loop combination to score 81 points.
Scherbakova said: "In general the whole skate was full of nerves,"
Mixed emotions for Kagiyama after second Grand Prix gold
"I had to watch every move, in general I am very satisfied that it all worked out. I am most satisfied with my [combination], it was the hardest jump in my program, and the most important one."
World record holder Alexandra Trusova emerged from the short program in 12th, way down on expectations.
Japan's Kihira Rika and Russian Elizaveta Tuktamysehva landed triple axels to finish second and third respectively with 79.08 and 78.86.
Medals will be decided on Friday with the free program in Stockholm.
Internationaux de France
‘So difficult and she made it look easy!’ - Shcherbakova doubles up in Grenoble
‘Look at the quality!’ - Kagiyama seals second Grand Prix win of season