Kamila Valieva comfortably outscored former training partner Alexandra Trusova to lead after the Cup of Russia short program in Moscow.
In her first competition since leaving coach Eteri Tutberidze for Evgeni Plushenko, Trusova's jumping was not quite on point as she scored 75.77.
Reigning world junior champion Valieva had a near-flawless skate, nailing her triple flip, double Axel and triple Lutz-triple toe loop combination.
It was all smiles in the Tutberidze camp as the 14-year-old scored 85.10 to take a sizeable advantage into Sunday's free skate with another Tutberidze youngster, Daria Usacheva, second on 80.39.
Valieva wins the day
Trusova prompted loud cheers from the crowd as she performed a triple Axel in the warm-up.
She was unable to repeat that in the short program itself, almost putting a hand down on landing.
The 17-year-old followed that with a solid triple flip and a triple Lutz-triple toe loop combination.
As she showed at last month's Russian test skates, Trusova has added artistry to her explosive jumping and her skate to 'Love Story' and 'Appassionata' earned her 75.77, a higher score than she achieved during last season.
ISU Junior Grand Prix commentator Ted Barton was among those impressed by her performance.
Russian TV was keen to add to the soap opera-style drama with a split-screen showing Trusova with Plushenko in the kiss-and-cry and Tutberidze's coaching team alongside slow-motion replays of her skate.
Next up was Usacheva who finished second to Valieva in March's World Junior Championships in Tallinn, Estonia.
Another 14-year-old, Usacheva skated to Nicole Kidman's version of 'One Day I'll Fly Away' and her jumping was excellent with a double Axel followed by a triple Lutz and a triple flip-triple toe loop combination.
She also showed great musical interpretation and took the lead with 80.39, almost 10 points higher than her personal best in ISU competition.
Valieva was last to go and delighted the crowd with a stunning skate to 'Storm' composed by Olympic team gold medallist Eric Radford.
While her jumping has attracted headlines previously, this was an incredibly mature display from the Kazan-born skater who will not be eligible for senior competition for another year.
Her score of 85.10 was more than 10 points better than her ISU personal best, leaving her on course for her first victory in senior competition.
Youth dominates men's short program
Evgeny Semenenko was the surprise leader after the men's short program.
The 17-year-old from St Petersburg, coached by Tatiana Mishina and Alexei Mishin, just held on to his opening quad Salchow before hitting a fine triple Axel followed by a triple flip-triple toe loop combination with a slightly shaky landing.
His routine to 'The City Which Doesn't Exist' by Igor Korneliuk earned him a rapturous reception and a score of 85.83.
Another 17-year-old, Artem Kovalev, is just behind in second place.
The Muscovite, who trains under Plushenko and Alexander Volkov and won Stage 1 last month in Syzran, scored 83.85 with a top-three finish almost certainly securing him one of 12 places in December's Russian Championships.
Despite having no quad jumps in his routine, Artem Lezheev took third place with 83.32 points, just ahead of former European silver medallist Alexander Samarin on 82.77 with Petr Gumennik fifth on 79.51.