Petrov was an eminent Soviet General who fought mainly in the Crimea and Caucasus. At the start of the war he was stationed with the 2nd Cavalry Division defending Odessa and was evacuated to the Crimea when it could no longer be held. Petrov was in charge of the defense of Sevastopol when the rest of the Crimea had been captured. He managed to keep the city for many months until the Germans launched a major assault in June 1942. Petrov continued to fight until July when Russian supplies and reinforcements failed to get through. Petrov was evacuated before the city fell on 3 July.
In the winter offensive of 1942-43 Petrov was Commander of the Black Sea Front which attacked the Germans in the Caucasus only to come to a standstill. Petrov finally managed to take Novorossiysk and the Taman and Kerch Peninsulas in September and October 1943, forcing the Germans back into the Crimea. He commanded the 2nd Belorussian Front but was removed after a short time. From August 1944-April 1945 Petrov then commanded the 4th Ukrainian Front with which he crossed the Carpathian passes from the north into Ruthenia in October and then turned west towards Slovakia where he was ordered to aid the partisans. However he was held up by difficulties afforded by the mountainous terrain. In the January 1945 offensive he turned north towards Poland and ended the war liberating parts of that country.