At the 2021 Russian Championships, Boikova/Kozlovskii attempted to mount a title defense despite only having a week to prepare, but encountered throw jump issues in both segments. They placed second in the short program, behind a clean Tarasova/Morozov, after Boikova stepped out of their throw triple Lutz. In the free skate, Boikova stepped out of the throw triple flip. Second in that segment as well, they won the silver medal behind Tarasova/Morozov.