The Mk. IX replaced the Mk. V in June 1942 and on September 12, 1942 a Mk. IX brought down a Ju-86R flying at 43,000 feet. Another major achievement of the Mk. IX took place on October 5, 1944 when 401 Squadron became the first allied aircraft to shoot down an Me-262 jet. Even with the arrival of the Griffon powered Mk. XIV the Mk. IX continued in service until the end of WWII. There were 5,665 Mk. IX Spitfires and its variants produced.
The RAF No. 315 Squadron "Deblinski" was a Polish fighter unit formed in January 1941. Francis Gabreski, the son of a Polish immigrant family, was anxious to fly so he enlisted and in 1942 was assigned to the RAF No. 315 Polish Squadron flying a Spitfire. Gabreski flew many missions in his Spitfire but didn’t score any victories. In February 1943 he was reassigned to the USAAF 8th Air Force and six months later, flying a P-47 he scored his first victory, an FW-190. By the end of WWII Gabby had 28.5 victories.