You've obviously never seen footage of Sugar Ray Robinson, easily best pound for pound boxer ever.
Robinson was 85-0 as an amateur with 69 of those victories coming by way of knockout, 40 in the first round. He turned professional in 1940 at the age of 19 and by 1951 had a professional record of 128-1-2 with 84 knockouts. Robinson held the world welterweight title from 1946 to 1951, and won the world middleweight title in the latter year. He retired in 1952, only to come back two and a half years later and regain the middleweight title in 1955. He then became the first boxer in history to win a divisional world championship five times