Complex sentence: LaMotta's six fight rivalry with Sugar Ray Robinson is one of the most notable in the sport, with LaMotta winning just one of the bouts, although each one was close and LaMotta dropped Robinson multiple times.
Split into simpler sentences: LaMotta's sixth rivalry fight with Sugar Ray Robinson is one of the most notable in the sport. With LaMotta winning just one of the bouts, each one was close as LaMotta dropped Robinson multiple times.