After Stalin's direct appeal to Churchill in October 1942, the Spitfire Vb (letter "b" was used to designate a type "b" wing carrying 4 Browning machine guns and 2 Hispano cannons) was supplied to the USSR from the reserves for the Middle East. By March 1943, 143 airlifted vehicles were immediately put into operation. Some of them operated along the Black Sea coast of the Caucasus, others defended Moscow. At the end of 1943, some Luftwaffe pilots from the JG 52 fighter squadron were somewhat surprised to meet 25 Spitfires in the battles of Orel, three hundred kilometers south of Moscow.
Until September 1941, the Bf 109E was the main enemy of the Spitfire. Although this aircraft had a slight advantage in flight performance at 6100 m and its armament was lighter, overall the Spitfire V was the best of the two aircraft. Then, in September, the first of the newest Fw 190s took part in the battles over France. With the exception of the Spitfire's smaller turning radius, the Fw 190 was preferable in all other respects - there is no doubt that the Spitfire was clearly inferior to the new Luftwaffe`s Fighter-bomber. The response was the hastily created Spitfire Mk. IX, by using the type Vc wing with a more powerful Merlin 61 engine.