Naoya Inoue's May 2 outing against Junto Nakatani earned 'The Monster' the biggest win of his career . Despite being handed some problems by his fellow countryman, the undisputed super bantamweight champion retained his titles via unanimous decision. The biggest boxing match in Japanese history, and one of the largest spectacles in recent years of the sport, further established Inoue as one of the modern greats. It even propelled Inoue to No. 1 in the pound-for-pound rankings . There are still notable fights potentially in the future for the 33-year-old. However, despite still seemingly being at the peak of his powers, Inoue's father has called for the fighter to retire. Shingo Inoue believes Naoya has already proven himself enough Naoya Inoue | IMAGO / AFLOSPORT Boxers have often hung up their gloves while still at the top of the sport, many of whom sailed into the sunset with their unbeaten records intact.…