straight punches from the outside, but he was also struck by Casamayor whenever he lunged forward. Two minutes into the eleventh round, Casamayor was knocked down by a right punch as he pulled away from an intense exchange. Casamayor was able to get on his feet, but it was clear he was still shaken from the knockdown. As soon as the action was allowed to resume, Márquez went in for the kill as he let his punches go in furious combination. Casamayor punched back, but he was knocked down again with about 7 seconds left in the round. Referee Tony Weeks stepped in the bout and stopped the fight as he deemed Casamayor unable to continue. The official judges had the fight scored 95–95, 95–95 and 97–93 for Márquez before the 11th-round knockout. After the win, The Ring ranked Márquez second on its pound for pound list and rated him the number one boxer in the lightweight division. Márquez vs. Diaz I On February 28, 2009, Márquez defeated former WBA, WBO & IBF Lightweight Champion Juan Díaz by knockout. Díaz controlled the fight early in the bout as the two boxers exchanged punches. Díaz opened a cut above Márquez's right eye in the fifth round and looked to control the bout, but Márquez responded by opening a gash above Díaz's right eye and stunning him with a left hook before the end of the eighth round. Márquez landed two hard rights to Díaz's face in a three-punch combination that knocked Díaz down with 35 seconds remaining in the ninth round. Díaz rose, but seconds later, Márquez followed with a right uppercut to the chin that knocked Díaz down for a second time. Referee Rafael Ramos waved an end to the fight after two minutes and 40 seconds of the ninth round. With the victory, Márquez defended his The Ring Lightweight title and claimed the vacant WBO and vacant WBA (Super) Lightweight titles. This bout was named "Fight of the Year" for 2009 by The Ring magazine and ESPN.com. After the fight, Márquez expressed an interest in fighting Floyd Mayweather Jr. Welterweight Márquez vs. Mayweather Márquez moved up to the welterweight division and fought undefeated pound for pound champion Floyd Mayweather Jr. The fight was scheduled to take place at 144-pound catch weight on July 18, 2009, at the MGM Grand Garden Arena; but was postponed due to a rib injury