Gennady Golovkin is a middleweight boxer.
Gennady Golovkin . As of May 2017 , he is ranked as the world 's best middleweight by BoxRec and the Transnational Boxing Rankings Board , and second best by The Ring . Later that year he defeated Marco Antonio Rubio to add the WBC interim middleweight title to his collection , and defeated David Lemieux in 2015 to win the IBF middleweight title . In his amateur career , Golovkin won a gold medal in the middleweight division at the 2003 World Championships .