Londoner Mitchell 's previous world title fight ended in defeat to Ricky Burns in 2012 .
Promoter Eddie Hearn is confident his man has the tools to dethrone Marquez - if he gets that far .
Londoner Mitchell 's previous world title fight ended in defeat to Ricky Burns in 2012 , but promoter Eddie Hearn is confident his man has the tools to dethrone Marquez - if he gets that far .