Rocky Marciano vs. Jersey Joe Walcott

Rocky Marciano is the only heavyweight champion to retire undefeated. This is the fight that had started his long reign as heavyweight champion of the world. Challenging Jersey Joe Walcott seemed like a mistake all through the fight, Marciano outscored by him on all rounds untill the 13th. A few seconds after the start of that round, Marciano's famous "Suzie Q" had hit the mark and had sent Walcott to hang knocked out on the ropes