The Fokker is lighter, so perhaps it's wing loading allowed it a better turn rate than the 109? <shrug> In 1939/1940 fighter tactics were rapidly evolving from WWI-style angles tactics into slashing, high-speed energy tactics. I'll bet that there must have been some 109 pilots who found out about that to their cost, when they tried to dogfight the DXXI.
Germans had already discovered this and made the transition for the largest part during & right after the Spanish Civil war, where the fast 109 fought much more maneuverable planes. Allied forces still used vic formation, Germans had switched to Schwarm & Rotte in Spain already.
