There she worked as a gym teacher and was active in various sports including horseback riding, cycling, rowing, swimming, basketball, skiing, hockey, and skating.

Initially, Petrova served in the 4th Division of the Leningrad People's Militia before entering a medical battalion, even though she was too old to be drafted.

In the Battle of Leningrad, Petrova trained other soldiers of the Red Army as snipers in addition to participating in direct combat.

[4][5] In early August 1944, while fighting on the 3rd Baltic Front, Petrova fought in a battle near the Lepassaare railway station in Estonia.

[6] While fighting on the 2nd Belorussian Front in the battle for the control of Elbing in February 1945, Petrova provided cover to her unit by attacking enemy positions with sniper fire, killing 32 enemy soldiers in that engagement and bringing her kill tally to 100 with her victories in Leningrad, Lepassaare, and other battles.