During World War II, he was active in the Soviet Union, premiering new concerti by Nikolai Miaskovsky and Aram Khachaturian as well as two sonatas by his friend Sergei Prokofiev. He was also awarded the Stalin Prize in 1942. The final years of the war saw the blossoming of a friendship with Shostakovich, which would lead to the two violin concertos and the sonata, all of which were to be premiered by and become firmly associated with Oistrakh in the following years. Oistrakh's career was set from this point, although the Soviet Union was "protective" of its people and refused to let him perform abroad. He continued to teach in the Moscow Conservatory, but when Nazi Germany invaded the Soviet Union, he went to the front lines, playing for soldiers and factory workers under intensely difficult conditions. Arguably one of the most heroic acts in his life was a performance of Tchaikovsky's Violin Concerto to the end in the central music hall during the Battle of Stalingrad in the winter of 1942 while central Stalingrad was being massively bombed by the German forces. However, other sources indicate that Oistrakh performed in Leningrad that winter. Whether Oistrakh performed in Stalingrad is unconfirmed.