He has identified Perez 's Achilles ' heel but declined to reveal what it was .
A southpaw , Mamadjonov is familiar with Perez 's strengths and weaknesses , having had the Colombian on his radar since they were both amateurs .
Mamadjonov has identified Perez 's Achilles ' heel but declined to reveal what it was .
A southpaw , Mamadjonov is familiar with Perez 's strengths and weaknesses , having had the Colombian on his radar since they were both amateurs .