Technically, Zanni never pitched a complete game in the majors, but he did pitch all nine innings of a victory. On June 22, 1962, he relieved injured Joel Horlen for the White Sox with two on and none out. He continued the rest of the way, scattering seven hits in a 5-1 win. Moreover, in the seventh inning, he was knocked unconscious in a collision while covering first base. After clearing his head, he went back to the mound and finished the game.