Night [gen-の] street [at-で] 2-[counter-人] [gen-の] man [subj-が] fight [obj-を] started.
けんかを始める ('start a fight') — けんか is the everyday word for 'fight, quarrel,' covering verbal and physical. 2人の男 uses the counter 人 adjectivally before 男. で marks the location of the action (the street).