Marciano would beaten either of them in a fight though so he’s the best fighter to retire with a perfect record
LOL Sorry but Mayweather is the LEAST likely. Too many dark clouds marr his chances It has to be The Rock!!! Mr Marciano
The Undefeated, Untied, and Undisputed best is Rocky Marciano, IMHO. It's very hard to pick between these 3. Mayweather had 2 Majority Decision wins and 1 Split Decision win, in 50 fights. Calzaghe had 2 Split Decision wins in 46 fights. Marciano had 1 Split Decision win in 49 fights. It's also interesting that the only 2 who went 12 or more rounds with Rocky (Walcott and Charles), were knocked out in 1 and 8 in rematches (and he really needed that Charles KO).
3 times. I was friends with a guy who personally knew Rocky Marciano and Willie Pep. I even had a meal with him once, in Philadelphia. (My friend and I lived in New Jersey at the time.) My friend paid. He told me, in advance, if you eat out with Rocky and Willie, you pay. I left the tip. That evening, Rocky had Spaghetti with tomato sauce, Salad, and Italian Bread (no butter). He had coffee and water to drink.