At six years and seven months his reign as undisputed middleweight champion is the second longest of the last century behind only Tony Zale .
Hagler made twelve undisputed title defenses and holds the highest KO % of all middleweight champions at 78 % .
At six years and seven months Hagler 's reign as undisputed middleweight champion is the second longest of the last century behind only Tony Zale .
Hagler made twelve undisputed title defenses and holds the highest KO % of all middleweight champions at 78 % .