Muhammad Ali 21 during an elimination bout following Rocky Marciano's retirement. Mike Tyson broke both records in 1986 when he defeated Trevor Berbick to win the heavyweight title at age 20. Soon after the Liston fight, Clay changed his name to Cassius X, and then later to Muhammad Ali upon converting to Islam and affiliating with the Nation of Islam. Ali then faced a rematch with Liston scheduled for May 1965 in Lewiston, Maine. It had been scheduled for Boston the previous November, but was postponed for six months due to Ali's emergency surgery for a hernia three days before. The fight
LaMar Clark bouts 27 were against boxers making their professional debut. His last fight was on April 19, 1961 against Muhammad Ali, then known as Cassius Clay. Ali knocked out Clark in the 2nd round breaking his nose. Clark retired after his fight with Ali. Clark died on November 5, 2006. LaMar Clark LaMar Clark (December 1, 1934 – November 5, 2006) was an American professional boxer who fought as a heavyweight boxer. He was active from 1958 to 1961 and fought a recorded 46 times in his 3 year-career. Clark has the current record of most consecutive knockouts at 44 (including