The short answer is just once. Born in Sand Slough, Arkansas in the early thirties – in the absence of a birth certificate, his actual date of birth is disputed – Charles ‘Sonny’ Liston became the leading contender for the world heavyweight title in 1960. However, despite having been beaten just once, by split decision – when suffering broken jaw in the first round against Marty Marshall in September, 1954 – Liston was snubbed by reigning champion Floyd Patterson because of his known links to Philadelphia racketeer Frank ‘Blinky’ Palermo.
Liston finally challenged Patterson at Comiskey Park, Chicago on 25 September 25, 1962 and needed just two minutes and six seconds of the opening round to knock out his opponent. Weighing in at 25lb heavier than Patterson, and boasting a 13″ reach advantage, Liston landed three heavy blows, which sent the champion reeling, and finished him off with a powerful left-right-left combination. The pair met again at the Convention Center, Las Vegas on July 22, 1963, with almost identical results; Liston twice knocked down Patterson before landing two jarring right hands and a left uppercut, which knocked him down for a third and final time after 2 minutes and 10 seconds of the opening round.
Dubbed ‘unbeatable’, Liston next faced 22-year-old Cassius Clay – soon to become Muhammad Ali – at the Convention Center, Miami on February 25, 1964. At the end of the fourth round, Clay complained that he had something burning in his eyes, blinding him; he managed to evade Liston until the sixth round, by which time his vision had cleared and he had taken control of the fight. Citing a shoulder injury, Liston failed to answer the bell for the seventh round and Clay was declared the winner by technical knockout.