Following the national championships, Mozalev competed in the 2021 Channel One Trophy, a televised event organized in lieu of the cancelled European Championships. He was selected for the Red Machine team captained by Alina Zagitova. He was fifth in the short program and fourth in the free skate, while the Red Machine won the trophy. After this, Mozalev prepared for the Russian Cup Final, which was widely assumed to be the deciding event for the second Russian men's berth at the 2021 World Championships in Stockholm. Mozalev was second in the short program despite doing only a triple flip instead of a quad. He fell three times in the free skate, dropping to fourth place overall.