Keith Thurman
In November 2012, Quintana (29-4, 23KOs) finally decided to call it a day. The Puerto Rican boxer announced his retirement after suffering a fourth-round TKO defeat to Keith Thurman (19-0, 18KOs) at the Citizens Business Bank Arena in Ontario, California on the 24th of that month. Throughout his career he won 29 of 33 professional contests, only coming up short against fellow world champion fighters Miguel Cotto, Paul Williams, Andre Berto and Keith Thurman.