Sergio Martinez KO1 Jhon Teheran... Former world middleweight champion Sergio Martinez is still plugging away at age 48. Fighting in his home county of Argentina, Martinez landed a combination that knocked out Jhon Teheran in the first round on Tuesday. Teheran is a 38 year-old Colombian who is now 18-3. Martinez (57-3-2) has now won six straight since his 2020 comeback started following six years out of the ring.