The 13-year-old, making her World Juniors debut, did not make an error in a strong and clean skate, using her "Picasso" program, that scored a personal best of 74.92.
South Korea's Lee Hae-in (70.08) put in one of her best performances to sit second, while Valieva's fellow Russian Daria Usacheva (68.45) is in third.
Valieva stars; Liu falters
All eyes were on the Valieva-Liu tussle coming into the event, with Liu's only defeat this season coming at the Russian's hands at the Junior Grand Prix Final.
Valieva does not have a triple Axel in her programs, but that was no impediment today.
She opened with a triple loop, and followed that with a double Axel for her second jumping pass.
A solid triple Lutz, triple toe loop combination executed with her arms high above her head on both jumps wrapped up her jumping elements. That combination also received the base value boost for coming in the second half of her program.
It was a program that impressed the judges, who awarded her a season-best 74.92 points.
"I skated quite well, except for the combination, there was a little mistake," she said in the press conference afterwards. "The landing was not perfect.
"I was a bit nervous before the competition, but I tried not to be nervous once I took my starting position, because that can’t be."
Liu, however, chose to put her combination jump – a triple Axel, triple toe loop – as her opening pass.
The 14-year-old hung on to the landing on her Axel, before under-rotating the toe loop.
She was further marked down on her step sequence, which was only judged a level 3, although her remaining jumps – a double Axel and a triple loop – were clean.
Her score meant she was unable to overtake Usacheva, while Lee overtook her in the final group.
Lee and Usacheva in the hunt
Lee's score of 70.08 bettered her previous personal best of 69.29.
She chose the same jumps as Valieva, although in a different order, choosing to start with the combination.
Her jump with the boosted base value was the triple loop.
Usacheva, meanwhile, was marked down on her triple flip, triple toe loop combination for an unclear edge on the flip and an under-rotation on the toe loop.
But a high Program Component Score ensured she would take the small bronze medal ahead of Liu.
The free skate takes place from 3:45 p.m. local time (1:45 p.m. UTC/GMT) on Saturday.