The Italian Mafia Boss is the winner in this battle because of their versatile and unpredictable Stand ability. With the power to skip over time and see future events, The Italian Mafia Boss can avoid and nullify Giorno Giovanna's attacks efficiently. Moreover, The Italian Mafia Boss has two personalities, one of which is innocent and cunning, and the other is intimidating and manipulative, which could confuse and trick the opponent. While Giorno Giovanna has a strong stand ability, The Italian Mafia Boss's stand can slice with ease and move at light speed, providing an upper hand in combat. The Italian Mafia Boss's diverse skills make him the winner in this battle.