Julio Cesar Martinez will now defend his WBC world flyweight title against Moises Calleros on Friday at Azteca Studios in Mexico City, live on DAZN. Martinez (16-1, 12 KOs) was due to face fellow countryman Maximino Flores but the IBO champion returned a positive test for COVID-19 and will be unable to challenge for Martinez’s green and gold strap.

Calleros (33-9-1 17 KOs) now has a golden opportunity to change his career overnight in Flores’ place. The 31-year-old landed the WBO NABO title at 112lbs last September and fights for world honors for the second time in his career having traveled to Japan in March 2018 to challenge WBO champion Ryuya Yamanaka.

Martinez’s clash with Calleros is part of a bumper world title triple-header in Mexico.

Juan Francisco Estrada (40-3 27 KOs) will defend his WBC super-flyweight title in a rematch with Carlos Cuadras (39-3-1 27 KOs) and Roman ‘Chocolatito’ Gonzalez (49-2 41 KOs) defends his WBA super flyweight title against Israel Gonzalez (25-3 11 KOs) – with Estrada and Chocolatito on a collision course for a rematch should they both emerge victorious.