The 2020 World Junior Championships were again seen by many as a showdown between Valieva and Alysa Liu, who had recently defended her title at the senior-level 2020 U.S. Championships. Valieva placed first in the short program ahead of Lee Hae-in of South Korea and Usacheva, setting a new personal best. Her score of 74.92 points was the second highest short program score ever for a junior lady, only behind training partner Alena Kostornaia's short program at the 2018–19 Junior Grand Prix Final. In the free skate, she performed similarly to the Russian Junior Championships, stepping out on her opening quadruple toe loop and landing all other jumps cleanly, including a second quadruple toe loop in combination. She won the title and became the new Junior World Champion ahead of Usacheva and Liu. Valieva remarked afterward that "there was a little mistake on the toe loop, but basically I am pleased with my performance."