Joshua, who kept his perfect KO record in tact to advance to 16-0 with 16 KOs, earned a heavyweight belt in the fewest number of fights since Michael Bentt beat Tommy Morrison in just his 12th pro match in 1993.
Joshua’s one-punch KO power was evident early. After an even first, the 2012 Olympic Gold Medalist floored Martin with a straight right less than one minute into the second round. The southpaw looked stunned and slowly rose to beat the count, but was floored again with another right hand just seconds later. That was it for Martin (23-1-1, 21 KOs), who had won the belt in January under bizarre circumstances and now owns the second shortest reign for a heavyweight champion.
“I’m only one-quarter of the way there,” said Martin, who has expressed his desire to unify the heavyweight division. “I’m not going to get too carried away because we still have work to do. We have (David) Haye calling me out, Tyson Fury calling me out. I need to keep on pushing if I’m going to maintain at a high level.
“Every heavyweight has power. It’s just about knocking and staying focused. I told you I would come out and punish him. This is just the reward of it.
“There will probably be some negativity that he was easy. The fact that he was willing to come to London says a lot about Charles Martin.”
Joshua becomes the sixth Olympic Super Heavyweight Gold Medalist to win a professional heavyweight title, joining Joe Frazier, George Foreman, Lennox Lewis, Wladimir Klitschko and Alexander Povetkin.
In bonus coverage on SHOWTIME BOXING INTERNATIONAL, Lee Selby survived a second round knockdown to defend his IBF Featherweight World Championship against challenger Eric Hunter in a unanimous decision victory scored 115-111, 116-110, 116-110.