The fastest two lengths in swimming came down to 0.22 seconds as Kyle Chalmers of Australia out-touched Pieter Timmers of Belgium Wednesday in Rio for his first Olympic gold in a time of 47.58.
Santo Condorelli of Canada turned first at the wall in a blazing 22.22 seconds but the 18-year-old Chalmers, who was seventh at the halfway mark, battled back on the field with dominating closing speed for the win.
Nathan Adrian, who anchored Team USA's upset win in the 4x100m freestyle relay on Sunday, turned his bent-arm freestyle into a straight-arm recovery as he finished third by 0.